Relationship between susceptibility to antimicrobials and virulence factors in paediatric Escherichia coli isolates

Co-existence of antibiotic resistance and virulence factors in carbapenem resistant Klebsiella pneumoniae clinical isolates from Alexandria, Egypt

BACKGROUND

The emergence and spread of carbapenem resistance among Enterobacteriaceae, particularly Klebsiella pneumoniae, constitute a serious threat to public health, since carbapenems are the last line of defense in the treatment of life-threatening infections caused by drug-resistant Enterobacteriaceae. The current study investigated the co-existence of different virulence factors and carbapenemases in carbapenem-resistant Klebsiella pneumoniae clinical isolates from Alexandria, Egypt.

RESULTS

Phenotypic characterization of virulence factors indicated that 41.5% of the isolates were strong biofilm producers, while hypermucoviscosity was detected in 14.9% of the isolates. All isolates harbored five or more virulence factor encoding genes. entB, ycfM, mrkD and fimH were detected in all isolates, while only one isolate was negative for ybtS. uge, iutA, rmpA and kpn were detected in 61 (64.8%), 55 (58.5%), 41 (43.6%) and 27 (28.7%) isolates, respectively, while all isolates lacked magA and k2A. Phenotypic detection of carbapenemases was explored by performing CarbaNP and mCIM/eCIM. CarbaNP test showed positive results in 98.9% of the isolates and positive mCIM tests were observed in all isolates, while 68 (72.3%) isolates showed positive eCIM tests. blaNDM was the most prevalent carbapenemase encoding gene (92.5%) followed by the blaOXA-48 (51.1%), while blaKPC was detected in only one (1.06%) isolate. blaVIM, blaIMP and blaGES were not detected in any of the tested isolates.

CONCLUSIONS

The widespread of carbapenem-resistant Klebsiella pneumoniae represents a major problem in health care settings. A significant association between certain virulence factors and carbapenemase-encoding genes was observed. Antibiotic stewardship programs and infection control policies should be effectively implemented especially in hospitals to limit the spread of such highly virulent pathogens.

Antimicrobial resistance of Escherichia coli isolated from retail foods in northern Xinjiang, China

To determine antimicrobial resistance, 431 samples of retail foods purchased at different supermarkets in Northern Xinjiang were examined in this study. There were 112 Escherichia coli strains that were isolated, with approximately 26% of the samples contaminated by E. coli. The detection rate of E. coli isolated from pork was the highest (59.6%), followed by mutton (52.6%), retail fresh milk (52.4%), duck (36.4%), beef (35.3%), chicken (33.3%), and ready-to-eat food (12.9%); the E. coli detection rate for fish and vegetables was <11%. The result showed that the 112 isolates were mostly resistant to tetracycline (52%), followed by ampicillin (42%), compound trimethoprim/sulfamethoxazole (37%), amoxicillin (33%), and nalidixic acid (32%), imipenem resistance was not detected. One hundred isolates carried at least one antimicrobial resistance gene. The detection rate of resistance genes of our study was as follows: tetA (38%), tetB (27%), bla OXA (40%), bla TEM (20%), floR (20%), sul1 (16%), sul2 (27%), aad Ala (19%), aadB (11%), strA (28%), and strB (24%); tetC and bla PSE were not detected. Virulence genes fimC, agg, stx2, fimA, fyuA, papA, stx1, and eaeA were found in 52, 34, 21, 19, 6, 3, 2, and 2 isolates, respectively; papC was not detected. There was a statistically significant association between fimC and resistance to ciprofloxacin (p = .001), gentamicin (p = .001), amikacin (p = .001), levofloxacin (p = .001), and streptomycin (p = .001); between fimA and resistance to tetracycline (p = .001), ampicillin (p = .001), compound trimethoprim/sulfamethoxazole (p = .001), and amoxicillin (p = .003); between agg and resistance to gentamicin (p = .001), tetracycline (p = .001), ciprofloxacin (p = .017), and levofloxacin (p = .001); and between stx2 and resistance to ampicillin (p = .001), tetracycline (p = .001), compound trimethoprim/sulfamethoxazole (p = .002), and amoxicillin (p = .015).

Snapshot of Phylogenetic Groups, Virulence, and Resistance Markers in Escherichia coli Uropathogenic Strains Isolated from Outpatients with Urinary Tract Infections in Bucharest, Romania

BACKGROUND

Urinary tract infections (UTIs) caused by Uropathogenic Escherichia coli (UPEC) are among the most common infections worldwide, including Romania. To the best of our knowledge, this is the first study performed on a significant number of community-acquired (CA) UPEC strains isolated from Romanian outpatients, aiming to evaluate and establish potential correlations among the phylogenetic groups (PG), resistance profiles, and the virulence factors (VF) genes of the CA-UPEC isolates.

MATERIALS/METHODS

The present study was performed on a total of 787 UPEC nonrepetitive isolates consecutively isolated during one month from outpatients with CA-UTIs, visiting one of the biggest laboratories in Bucharest, Romania, receiving patients from all over the country. The strains identification was performed by MALDI TOF and the susceptibility patterns were tested using Microscan according to CLSI guidelines. PCR assays were performed to detect the presence of different VFs (fimH gene encoding for type 1 fimbriae, afaBC for A fimbriae, sfaDE for S fimbriae, KpsMTII for capsule, hlyA for haemolysin A, hlyD for haemolysin D, and cnf-1 for tumor necrosis factor), the phylogenetic groups (PG) A, B1, B2, and D, and the extended spectrum beta-lactamases (ESBLs) genes.

RESULTS

The 787 CA-UPEC strains were isolated predominantly from female patients (90.95%) of >30 years (~74%). The resistance rates were 47.52% for ampicillin, 41.16% for tetracycline, 24.39% for cotrimoxazole, 19.18% for amoxicillin-clavulanic acid, 15.50% for cefazolin, 14.99% for ciprofloxacin, and 14.86% for levofloxacin; 35.19% of the investigated strains were MDR and 9.03% ESBL producers (from which 42.25% were positive for blaCTX-M, 38.02% for blaTEM, and 19.71% for blaSHV). FimH was the most frequent virulence gene (93.90%) followed by hlyD (44.34%); afaBC (38.24%); KpsMTII (32.65%); sfaDE (23.88%); hlyA (12.45%); and cnf-1 (7.75%). The distribution of the analyzed UPEC strains in phylogenetic groups was different for non-MDR and MDR strains. Overall, 35% of the strains belonged to the phylogenetic group B2 (harboring the yjaA gene); 27% to group B1 (confirmed by the presence of the TspE4C2 fragment); 16% to group D; and 22% to group A. The CA-UPEC strains included in PG B1 and PG B2 proved to be the most virulent ones, the number of strains carrying multiple VFs (>3) being significantly larger as compared to strains belonging to PG A and PG D) (p<0,0001). The presence of one or two ESBL genes was significantly associated (p =0.0024) with PGs A and D.

CONCLUSIONS

Our findings showed that the community UPEC strains circulating in Bucharest, Romania, belong predominantly to group B2 and >90% harbored the fimH gene. High MDR resistance rates were observed, as well as extended VF profiles, highlighting the importance of this type of studies for improving the epidemiological surveillance and the therapeutic or prophylactic management of the respective infections, in the context of antibiotic resistance emergence.

Distribution of Virulence Factors According to Antibiotic Susceptibility among Escherichia coli Isolated from Urinary Tract Infection

Escherichia coli is the major causative pathogen of urinary tract infection (UTI) in humans. Virulence and drug resistance play important roles in the pathogenesis of E. coli infections. The aims were to investigate the presence of uropathogenic virulence genes and to evaluate a relationship between antibiotic resistance and virulence in E. coli from UTI. A total of 132 E. coli were collected between April and June 2015 in two hospitals of Sanandaj, Iran. Isolates were examined for susceptibility to 16 antibiotic disks using the disk diffusion method and for possession of virulence genes by polymerase chain reaction. Associations between antimicrobial resistance and virulence genes were investigated. A P < 0.05 was considered significant. Of the 132 isolates, the most prevalent virulence gene was pap (31.1%), followed by cnf (28.8%), hly (16.7%), and afa (10.6%). Different patterns of virulence genes were identified. A significant association was detected between the simultaneous presence of hly and pap. The most effective antibiotics were nitrofurantoin, cefoxitin, and imipenem and the least effective were ampicillin, trimethoprim-sulfamethoxazole, and cefotaxime. An association was seen between the presence of cnf and susceptibility to the certain antibiotics, whereas strains with a reduced susceptibility to the certain antibiotics were associated with a significantly increased prevalence of afa and hly (P < 0.05). These findings suggest a correlation between the presence of virulence gene and resistance in E. coli strains from UTI. The results indicate that there is a need for surveillance programs to monitor drug resistance in pathogenic E. coli.

Genotypic analysis of Escherichia coli strains that cause urosepsis in the Aegean region

BACKGROUND/AIM

The aim of this study was to characterize strains genotypically, to determine their phylogenetic relationships, to investigate the presence of the papG gene, and to compare their antibiotic susceptibility test results.

MATERIALS AND METHODS

Seventy pathogenic E. coli strains were isolated from both urine and blood cultures of patients with the preliminary diagnosis of urosepsis who were referred to the Ege University Faculty of Medicine, Bacteriology Laboratory of Medical Microbiology Department in İzmir. All of these strains were examined for the papG gene and phylogenetic groups with the multiplex polymerase chain reaction technique. Pulsed-field gel electrophoresis and multilocus sequence typing (MLST) were used for epidemiologic analysis.

RESULTS

Phylogenetically, it was found that 16 belonged to group B2, 31 belonged to group D, 15 belonged to group A, and 7 belonged to group B1. One strain was not identified as belonging to a group. papG genes were found in 26 of 70 E. coli strains. Thirty urosepsis pathogenic E. coli strains were analyzed with MLST. Twenty-two strains were identified as new STs.

CONCLUSION

These findings are extremely important for Turkey and these new 22 strains should be investigated in more detail because they are new and have the potential to lead to infections.

Quantifying Attachment and Antibiotic Resistance of from Conventional and Organic Swine Manure

Broad-spectrum antibiotics are often administered to swine, contributing to the occurrence of antibiotic-resistant bacteria in their manure. During land application, the bacteria in swine manure preferentially attach to particles in the soil, affecting their transport in overland flow. However, a quantitative understanding of these attachment mechanisms is lacking, and their relationship to antibiotic resistance is unknown. The objective of this study is to examine the relationships between antibiotic resistance and attachment to very fine silica sand in collected from swine manure. A total of 556 isolates were collected from six farms, two organic and four conventional (antibiotics fed prophylactically). Antibiotic resistance was quantified using 13 antibiotics at three minimum inhibitory concentrations: resistant, intermediate, and susceptible. Of the 556 isolates used in the antibiotic resistance assays, 491 were subjected to an attachment assay. Results show that isolates from conventional systems were significantly more resistant to amoxicillin, ampicillin, chlortetracycline, erythromycin, kanamycin, neomycin, streptomycin, tetracycline, and tylosin ( < 0.001). Results also indicate that isolated from conventional systems attached to very fine silica sand at significantly higher levels than those from organic systems ( < 0.001). Statistical analysis showed that a significant relationship did not exist between antibiotic resistance levels and attachment in from conventional systems but did for organic systems ( < 0.001). Better quantification of these relationships is critical to understanding the behavior of in the environment and preventing exposure of human populations to antibiotic-resistant bacteria.

Microbiological quality of water from the rivers of Curitiba, Paraná State, Brazil, and the susceptibility to antimicrobial drugs and pathogenicity of Escherichia coli

Water safety is determined by several markers, and Escherichia coli is one of the most important indicators of water quality. The objective of this study was to evaluate the microbiological parameters in environmental samples of fresh water from rivers of Curitiba and its metropolitan area in Paraná State, Brazil. In addition, we evaluated the pathogenicity and susceptibility to antimicrobial drugs in E. coli. These evaluations were performed by quantitative and qualitative methods employing selective media for isolating thermotolerant coliforms and biochemical tests for identifying E. coli. Pathogenic strains of E. coli were detected by PCR multiplex using specific primers. From the water samples, 494 thermotolerant coliforms were obtained, of which 96 (19.43%) isolates were characterized as E. coli. Three isolates were identified as enteroaggregative E. coli, one as enterotoxigenic E. coli, one as enteropathogenic E. coli, and two carried the Eae virulence gene. E. coli susceptibility to commonly employed antimicrobial drugs was analyzed by the disc diffusion method. The results showed 49 (51.04%) isolates resistant to all the drugs assayed, 16 (16.67%) with an intermediate resistance to all drugs, and 31 (32.29%) intermediately or fully resistant to one or more drugs tested. The highest rate of resistance was observed for tetracycline 30 μg, streptomycin 10 μg, and ceftazidime 30 μg. Detection of E. coli is associated with water contamination by fecal material from humans and warm-blooded animals. The occurrence of resistant strains can be the result of the indiscriminate use of antimicrobial drugs and poor sanitation in the areas assayed.

Biofilm and fluoroquinolone resistance of canine Escherichia coli uropathogenic isolates

Background

Escherichia coli is the most common uropathogen involved in urinary tract infection (UTI). Virulence of strains may differ, and may be enhanced by antimicrobial resistance and biofilm formation, resulting in increased morbidity and recurrent infections. The aim of this study was to evaluate the in vitro biofilm forming capacity of E. coli isolates from dogs with UTI, by using fluorescent in situ hybridization, and its association with virulence genes and antimicrobial resistance.

Findings

The proportion of biofilm-producing isolates significantly increased with the length of incubation time (P < 0.05). Biofilm production was significantly associated with fluoroquinolone resistance at all incubation time points and was independent of the media used (P < 0.05). Biofilm production was not associated with cnf1, hly, pap and sfa genes (P > 0.05), but was significantly associated with afa, aer and the β-lactamase genes (P < 0.05).

Conclusions

To the best of our knowledge, this is the first report showing significant association between biofilm production and fluoroquinolone resistance in E. coli isolates from dogs with UTI. Biofilm formation may contribute to UTI treatment failure in dogs, through the development of bacterial reservoirs inside bladder cells, allowing them to overcome host immune defenses and to establish recurrent infections.

The Association of Virulence Determinants of Uropathogenic Escherichia coli With Antibiotic Resistance

Background:

The emergence of antimicrobial resistant strains of Escherichia coli has raised considerable interest in understanding the diversity and epidemiology of E. coli infections in humans. Virulence factors of E. coli determine the specific infections caused by this microorganism.

Objectives:

This study aimed to determine the prevalence of eight E. coli virulence factors and their association with antimicrobial resistance in bacteria isolated from patients with urinary tract infections (UTI).

Patients and Methods:

One thousand patients with UTI were enrolled in this cross-sectional study. Antimicrobial susceptibility was examined by disc diffusion method according to CLSI guidelines. After DNA extraction, the materials were probed by PCR for eight virulence factors genes, namely fimH, hly, iucC, ibeA, sfa/foc, neuC, papC, and afa genes.

Results:

The frequency of virulence factors papC, afa, sfa/foc, fimH, hly, neuC, ibeA, and iucC were 53.3%, 51.7%, 53.3%, 56.7%, 23.3%, 31.7%, 20%, and 73.3%, respectively. In addition, there was a high degree resistance to cotrimoxazole and nalidixic acid while a high degree of susceptibility to nitrofurantoin was detected. There was a statistically significant association between fimH gene and resistance to ciprofloxacin (P = 0.006), nalidixic acid (P = 0.025), and cotrimoxazole (P = 0.02). Such associations were found between ibeA gene and amikacin (P = 0.02) and cotrimoxazole (P = 0.02) as well as between afa gene and gentamycin (P = 0.05).

Conclusions:

The results showed that E. coli isolated from patients with UTI had eight virulence factors with high frequencies. Moreover, these results alleged a direct connection between virulence factors and antimicrobial resistance in E. coli.

Association of antibiotic resistance in agricultural Escherichia coli isolates with attachment to quartz

Surface water can be contaminated by bacteria from various sources, including manure from agricultural facilities. Attachment of these bacteria to soil and organic particles contributes to their transport through the environment, though the mechanism of attachment is unknown. As bacterial attachment to human tissues is known to be correlated with antibiotic resistance, we have investigated here the relationship between bacterial attachment to environmental particles and antibiotic resistance in agricultural isolates. We evaluated 203 Escherichia coli isolates collected from swine facilities for attachment to quartz, resistance to 13 antibiotics, and the presence of genes encoding 13 attachment factors. The genes encoding type I, EcpA, P pili, and Ag43 were detected, though none was significantly related to attachment. Quartz attachment was positively and significantly (P < 0.0038) related to combined resistance to amoxicillin/streptomycin/tetracycline/sulfamethazine/tylosin/chlortetracycline and negatively and significantly (P < 0.0038) related to combined resistance to nalidixic acid/kanamycin/neomycin. These results provide clear evidence for a link between antibiotic resistance and attachment to quartz in agricultural isolates. We propose that this may be due to encoding by the responsible genes on a mobile genetic element. Further exploration of the relationship between antibiotic resistance and attachment to environmental particles will improve the understanding and modeling of environmental transport processes, with the goal of preventing human exposure to antibiotic-resistant or virulent microorganisms.

The role of host factors and bacterial virulence genes in the development of pyelonephritis caused by Escherichia coli in renal transplant recipients

BACKGROUND AND OBJECTIVES

The aim of this study was to determine the role of host factors and bacterial virulence genes in the development of pyelonephritis caused by Escherichia coli in renal transplant (Tx) recipients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A total of 328 E. coli isolates from cases of cystitis (Cys; n=239) or pyelonephritis (PN; n=89), with 169 from renal Tx recipients, were subjected to molecular analyses to identify P-fimbria subunits (PapC, PapG II, and PapGIII), G- and M-fimbriae, and aerobactin. The presence of antibiotic resistance was also determined. Parameters such as gender, age, immunosuppression regimens, causes of ESRD, kidney donor, intraoperative anastomosis, use of double J stent, trimethoprim/sulfamethoxazole (TMP/SMZ) prophylaxis, and time after Tx were evaluated.

RESULTS

A multivariate analysis showed a significant association between PN and renal Tx. In renal Tx recipients, the risk of occurrence of PN was significantly higher among males and for those no longer receiving TMP/SMZ prophylaxis. E. coli strains isolated from PN presented a lower prevalence of papGIII and lower rates of resistance to pipemidic acid. Although papGII was more prevalent in PN than in Cys, it was not independently associated with PN.

CONCLUSIONS

These findings suggested that renal Tx increases the risk for PN, and the male sex represented a host factor independently associated with risk, whereas the prophylaxis with TMP/SMZ was protective. The lack of papGIII and low resistance to first-generation quinolones were bacterial-independent risk factors for PN in Tx.