Characterization of Antimicrobial Resistance and Class 1 Integrons Found inEscherichia coliIsolates from Human Stools and Drinking Water Sources in Jordan

Prevalence of antimicrobial resistance in a full-scale drinking water treatment plant

Antibiotic resistance in drinking water has received increasing attention in recent years. In this study, the occurrence and abundance of antibiotic resistance genes (ARGs) in a drinking water treatment plant (DWTP) was comprehensively investigated using metagenomics. Bioinformatics analysis showed that 381 ARG subtypes belonging to 15 ARG types were detected, and bacitracin had the highest abundance (from 0.26 × 10-2 to 0.86 copies/cell), followed by multidrug (from 0.57 × 10-1 to 0.47 copies/cell) and sulfonamide (from 0.83 × 10-2 to 0.35 copies/cell). Additionally, 933 ARG-carrying contigs (ACCs) were obtained from the metagenomic data, among which 153 contigs were annotated as pathogens. The most abundant putative ARG host was Staphylococcus (7.9%), which most frequently carried multidrug ARGs (43.2%). Additionally, 38 high-quality metagenome-assembled genomes (MAGs) were recovered, one of which was identified as Staphylococcus aureus (Bin.624) and harboured the largest number of ARGs (n = 16). Using the cultivation technique, 60 isolates were obtained from DWTP samples, and Staphylococcus spp. (n = 11) were found to be dominant in all isolates, followed by Bacillus spp. (n = 17). Antimicrobial susceptibility testing showed that most Staphylococcus spp. were multidrug resistant (MDR). These results deepen our understanding of the distribution profiles of ARGs and antibiotic resistant bacteria (ARB) in DWTPs for potential health risk evaluation. Our study also highlights the need for new and efficient water purification technologies that can be introduced and applied in DWTPs.

Into the sea: Antimicrobial resistance determinants in the microbiota of little penguins (Eudyptula minor)

Terrestrial and aquatic birds have been proposed as sentinels for the spread of antimicrobial resistant bacteria, but few species have been investigated specifically in the context of AMR in the marine ecosystem. This study contrasts the occurrence of class 1 integrons and associated antimicrobial resistance genes in wild and captive little penguins (Eudyptula minor), an Australian seabird with local population declines. PCR screening of faecal samples (n = 448) revealed a significant difference in the prevalence of class 1 integrons in wild and captive groups, 3.2% and 44.7% respectively, with genes that confer resistance to streptomycin, spectinomycin, trimethoprim and multidrug efflux pumps detected. Class 1 integrons were not detected in two clinically relevant bacterial species, Klebsiella pneumoniae or Escherichia coli, isolated from penguin faeces. The presence of class 1 integrons in the little penguin supports the use of marine birds as sentinels of AMR in marine environments.

Occurrence and distribution of five antibiotic resistance genes during the loading period in sludge treatment wetlands

The objectives of this study were to clarify the distribution as well as the removal mechanism of antibiotic resistance genes (ARGs) within three sludge treatment wetlands (STWs) during a loading period of two years. Three STW units were constructed and run during the loading period: Unit 1 (U1) built with aeration tubes, Unit 2 (U2) built with aeration tubes and reeds, and Unit 3 (U3) built with reeds only. All targeted ARGs, intI1, and 16S rRNA were detected in residual sludge in the order of magnitude: 16S rRNA>sul1>intI1>sul2>tetC>tetA>ermB. The abundance of the five targeted ARGs, intI1, and 16S rRNA increased in residual sludge, during the loading period, which may be due to the increase in bacteria caused by the continuous import of exogenous nutrients. However, STWs can also remove ARGs from sewage during the loading period and the mean removal efficiency of five resistance genes was 73.0%. The removal rates of intI1 and 16S rRNA were 73.5% and 78.6%, respectively. Positive correlations were detected in abundance of most ARGs and intI1, as well as 16S rRNA (P < 0.05), indicating intI1 plays a vital part in the propagation of ARGs. The removal of bacteria harboring these genes also occurs in the STW units.

Treated wastewater used in fresh produce irrigation in Nsukka, Southeast Nigeria is a reservoir of enterotoxigenic and multidrug-resistant Escherichia coli

Background

Occurrences of pathogens in environmental and irrigation waters, as well as the use of inadequately treated sewage for fresh produce constitute potential public health threats worldwide.

Objective

To investigate the treated wastewater used in fresh produce irrigation in Nsuskka, Southeastern Nigeria, as a reservoir enterotoxigenic and multidrug-resistant Escherichia coli.

Methods

Treated wastewater (from the sewage treatment facility at Nsukka, Southeast Nigeria), soil and irrigated vegetable samples were collected and analyzed using standard procedures. Escherichia coli isolated from the samples were screened for the presence of enterotoxigenic E. coli strain encoding lt gene and profiled for antibiotic resistance using the conventional PCR and standardized agar disk diffusion assays respectively.

Results

Of the total presumptive 103 isolates, PCR detected uidA gene in 87 (84 %), of which 23 (26 %) harboured the lt encoding ETEC gene. Generally, imipenem, cefuroxime and norfloxacin proved to be most effective of all the antibiotics employed. Wastewater isolates were variously susceptible to ciprofloxacin (95 %), norfloxacin (95 %), cefuroxime (93 %), chloramphenicol (93 %), trimethoprim and tetracycline (88 %), soil isolates to streptomycin (75 %) and vegetable isolates to cefuroxime (90 %), norfloxacin (86 %), ciprofloxacin (81 %) and chloramphenicol. Contrariwise, high resistances observed to other antibiotics were in the order; ampicillin (95 %), penicillin (93 %), erythromycin (90 %) and clarithromycin (83 %) among wastewater isolates, ciprofloxacin and norfloxacin (75 %) in soil isolates; penicillin, vancomycin and erythromycin (98 %), rifampicin and clarithromycin (93 %), sulphamethoxazole (83 %), ampicillin (81 %), tetracycline and imipenem (76 %), trimethoprim (72 %) and amoxicillin (71 %) among vegetable isolates, with multidrug resistance patterns ranging from three to seventeen.

Conclusions

Our results reveal the treated wastewater as a reservoir of enterotoxigenic E. coli as well as multidrug resistance that may pose a health hazard for humans and animals when released to the natural environment. Hence, there is need to develop management strategies and ensure compliance in order to prevent water-borne diarrhoea caused by ETEC and reduce the menace of antibiotic resistance in the environment.

Class 1 Integrons in Clinical Multi Drug Resistance <i>E. coli</i>, Sana'a Hospitals, Yemen

BACKGROUND AND OBJECTIVES

The occurrence of multi-drug resistance (MDR) Escherichia coli is one responsible for raised mortality and morbidity and was reported as major health problem. Class 1 integrons has crucial role in distributing antibiotic resistance genes among bacteria. Present work was aimed to determine the prevalence of class 1 integrons and its association with antibiotic resistance in MDR E. coli isolated from patient's body fluid and tissues from 6 health centers in Sana'a, Yemen.

MATERIALS AND METHODS

A cross-sectional study a total of 198 E. coli from patients diagnosed with infection that had been referred to 6 hospitals and medical diagnostic from July, 2017 to August, 2017 in Sana'a, Yemen. Susceptibility of E. coli isolates to 15 antibiotics using the disc diffusion method. Conventional polymerase chain reaction was used for detection of class 1 of integrons in 100 randomly selected MDR E. coli.

RESULTS

Overall 174 (87.9%) of 198 E. coli isolates were MDR. Class 1 integrons were detected in 67% of the randomly selected 100 of 198 MDR E. coli. A significant range (p<0.05-p<0.0001) was identified between presence of class 1 integrons and resistance to ceftriaxone, aztreonam, cefepime, amoxicillin-clavulanic acid, cefotoxime, cefepime-clavulanic acid, ceftazidime-clavulanic acid, ciprofloxacin, ceftazidime, norfloxacin and trimethoprim-sulfamethoxazole, while no significant difference were identified between integron class 1 and resistance to gentamicin, amikacin, nitrofurantoin and imipenem.

CONCLUSION

High MDR E. coli isolates were detected in this study, among them the prevalence of class 1 integrons is the most common. The significant association between class 1 integrons and resistance to common prescribed antibiotics in hospitals in Sana'a, Yemen.

Investigating possible association between multidrug resistance and isolate origin with some virulence factors of Escherichia coli strains isolated from infant faeces and fresh green vegetables

AIMS

In this study, the association between multidrug resistance (MDR) and the expression of some virulence factors were evaluated in Escherichia coli strains isolated from infant faeces and fresh green vegetables. The effect of isolate origin on associated virulence factors was evaluated. In addition, genetic fingerprinting of a sample of these isolates (10 isolates from each group) was studied in order to detect any genetic relatedness among these isolates.

METHODS AND RESULTS

Escherichia coli isolates were divided into four groups based on their origin (human faeces or plant) and their antibiotic resistance (multiresistance or susceptible). PCR was used to investigate heat-labile and heat-stable enterotoxin genes, and four siderophore genes (aerobactin, enterobactin, salmochelin and yersiniabactin). Genetic fingerprinting of the isolates was performed using enterobacterial repetitive intergenic consensus PCR. Siderophore production was measured by a colorimetric method. Biofilm formation was evaluated by a crystal violet assay. The results of the study showed that the expression of MDR is not significantly associated with an increase in these virulence factors or with biofilm formation. However, the origin of isolates had a significant association with siderophore gene availability and consequently on the concentrations of siderophores released. Genetic fingerprinting indicated that human and plant isolates have the same clonal origin, suggesting their circulation among humans and plants.

CONCLUSION

Antibiotic-susceptible strains of E. coli may be as virulent as MDR strains. Results also suggest that the environment can play a potential role in selection of strains with specific virulence factors.

SIGNIFICANCE AND IMPACT OF THE STUDY

Antibiotic-susceptible isolates of Escherichia coli from plant or human origin can be as virulent as the multidrug resistance (MDR) ones. Genetic relatedness was detected among the isolates of plant and human origin, indicating the circulation of these bacteria among human and plants. This could imply a potential role for environmental antimicrobial resistant bacteria in human infection.

Evaluation of antibiotic dispensing practice in community pharmacies in Jordan: A cross sectional study

It is well known that the emergence of antibiotic resistance is linked to the misuse and overuse of antibiotics. Misuse includes self-medication and the inappropriate use of antibiotics because of improper dosage or improper duration than recommended. This study investigated three patterns of dispensing antibiotics in a sample of community pharmacies in Jordan. This included dispensing antibiotics by prescription or over-the-counter either by direct request or upon a pharmacist’s recommendation. The antibiotics dispensed were evaluated in terms of indication, appropriateness of dose, and duration of treatment based on the empirical treatment suggested by selected references: Lexicomp (2017) and UptoDate (2017) and the manufacturer’s recommendations. Of the 457 antibiotics dispensed, almost one third were without prescription. Of the antibiotics dispensed with prescription or without prescription, 31.5% and 24.6% respectively were appropriate dosage and duration (p = 0.002). In the three patterns of dispensing, beta lactam antibiotics were the most commonly dispensed. In addition, it was noticed that there was a tendency to prescribe or dispense higher generations of antibiotics to cases that could have been treated with lower generation or safer antibiotics. Furthermore, 12.2% of the antibiotics were dispensed to treat infections that are not indicated for them. In conclusion, a significant proportion of antibiotics are dispensed without prescription in Jordan. Moreover, a considerable proportion of prescribed antibiotics were inappropriate for the conditions concerned. This indicates the importance of enforcing the Jordanian regulations prohibiting the dispensing of nonprescription antibiotics and the implementation of continuous education to physicians and pharmacists to increase awareness about the emergence of antibiotic resistance.

Evaluation of attenuation of pharmaceuticals, toxic potency, and antibiotic resistance genes in constructed wetlands treating wastewater effluents

The performance of constructed wetlands (CWs) in the removal of pharmaceutically active compounds (PhACs) is generally evaluated on the basis of chemical analysis. In this work, we used a combination of chemical, toxicological, and molecular analyses to assess the attenuation of PhACs, toxic potency and antibiotic resistance genes (ARGs) in a field study of three CWs serving as tertiary treatment of wastewater treatment plants. First, 17 PhACs were analysed chemically, of which 14 were detected and seven at concentrations >0.1μg/l. Even though some of the individual PhACs were moderately or highly removed in the CWs investigated, median removal of overall PhACs was approximately 50% in the vertical subsurface flow CW (VSF-CW) with a lower hydraulic loading rate while the removal in the other two free water surface flow CWs (SF-CWs) was negligible. Second, toxic potency of wastewater extracts was assessed in a range of bioassays. Estrogenicity was overall attenuated in CWs, while the neurotoxic potency of wastewater extracts did not decrease after passage through the two CWs investigated. Third, the VSF-CW and one of the SF-CW showed a positive removal of an integrase gene and three ARGs tested. The increased concentrations of ARGs in the other SF-CW, as well as the increase of total bacteria in all CWs, may relate to regrowth of resistance-carrying bacteria. Finally, multivariate analysis shows that most PhACs are positively correlated to the observed toxic potency. Additionally, low removal of organics and nutrients seems to parallel with low removal of PhACs. ARGs positively correlated with organics, nutrients and some PhACs, and the integrase gene but not to the respective antibiotics. The insufficient removal of PhACs, toxic potency, and ARGs indicates the need of an optimal design of CWs as tertiary treatment facilities.

Multiple antibiotic resistance indexing of Escherichia coli to identify high-risk sources of faecal contamination of water

We evaluated the antibiogram profile of Escherichia coli (n = 300) isolated from selected rivers in Osun State, Nigeria. The identities of the E. coli isolates were confirmed by polymerase chain reaction (PCR) technique. Susceptibility of the isolates to 20 antibiotics conventionally used in clinical cases was assessed in vitro by the standardized agar disc-diffusion method. All the isolates were susceptible to imipenem, meropenem, amikacin and gatilofloxacin. The isolates were variously susceptible to the other antibiotics as follows: ciprofloxacin (96 %), kanamycin (95 %), neomycin (92 %), streptomycin (84 %), chloramphenicol (73 %), nalidixic acid (66 %), nitrofurantoin (64 %), gentamycin (63 %), doxycycline (58 %), cefepime (57 %), tetracycline (49 %) and cephalothin (42 %). The multiple antibiotic resistance indexing ranged from 0.50 to 0.80 for all the sampling locations and exceeded the threshold value of 0.2, suggesting the origin of the isolates to be of high antimicrobial usage. Our findings signify an increase in the incidence of antimicrobial resistance of E. coli towards conventionally used antibiotics necessitating proper surveillance programmes towards the monitoring of antimicrobial resistance determinants in water bodies.

Longitudinal characterization of resistant Escherichia coli in fecal deposits from cattle fed subtherapeutic levels of antimicrobials

Model fecal deposits from cattle fed or not fed antimicrobial growth promoters were examined over 175 days in the field for growth and persistence of total Escherichia coli and numbers and proportions of ampicillin-resistant (Amp(r)) and tetracycline-resistant (Tet(r)) E. coli. In addition, genotypic diversity and the frequency of genetic determinants encoded by Amp(r) and Tet(r) E. coli were investigated. Cattle were fed diets containing chlortetracycline (44 ppm; A44 treatment group), chlortetracycline plus sulfamethazine (both at 44 ppm; AS700 treatment group), or no antibiotics (control). Fecal deposits were sampled 12 times over 175 days. Numbers of Tet(r) E. coli in A44 and AS700 deposits were higher (P < 0.001) than those of controls and represented up to 35.6% and 20.2% of total E. coli, respectively. A time-by-treatment interaction (P < 0.001) was observed for the numbers of Tet(r) and Amp(r) E. coli. Except for Amp(r) E. coli in control deposits, all E. coli numbers increased (P < 0.001) in deposits up to day 56. Even after 175 days, high Tet(r) E. coli numbers were detected in A44 and AS700 deposits [5.9 log(10) CFU (g dry matter)(-1) and 5.4 log(10) CFU (g dry matter)(-1), respectively]. E. coli genotypes, as determined by pulsed-field gel electrophoresis, were diverse and were influenced by the antimicrobial growth promoter and the sampling time. Of the determinants screened, bla(TEM1), tetA, tetB, tetC, sul1, and sul2 were frequently detected. Occurrence of determinants was influenced by the feeding of antimicrobials. Fecal deposits remain a source of resistant E. coli even after a considerable period of environmental exposure.

Antimicrobial resistance and association with class 1 integrons in Escherichia coli isolated from turkey meat products

The objective of this study was to quantify the role of class 1 integrons in antimicrobial resistance in Escherichia coli isolated from turkey meat products purchased from retail outlets in the Midwestern United States. Of 242 E. coli isolates, 41.3% (102 of 242) tested positive for class 1 integrons. A significant association was shown between presence of class 1 integrons in E. coli isolates and the resistance to tetracycline, ampicillin, streptomycin, gentamicin, sulfisoxazole, and trimethoprim-sulfamethoxazole. Attributable risk analysis revealed that for every 100 E. coli isolates carrying class 1 integrons, resistance was demonstrated for ampicillin (22%), gentamycin (48%), streptomycin (29%), sulfisoxazole (40%), trimethoprim-sulfamethoxazole (7%), and tetracycline (26%). Non-integron-related antimicrobial resistance was demonstrated for ampicillin (65%), gentamycin (16.9%), streptomycin (42.1%), sulfisoxazole (35.8%), and tetracycline (49.7%). Population-attributable fraction analysis showed that class 1 integrons accounted for the following resistances: gentamycin, 71% (50 of 71), amoxicillin-clavulanic acid, 19.6% (6 of 33), nalidixic acid, 34% (7 of 21), streptomycin, 28% (30 of 107), sulfisoxazole, 38% (40 of 106), and tetracycline, 14%, (26 of 185). In conclusion, although class 1 integrons have been implicated in resistance to antimicrobial agents, other non-integron resistance mechanisms seem to play an important part.