Molecular characterization and prevalence of β-lactamase-producing Enterobacterales in livestock and poultry slaughterhouses wastewater in Iran

Beta-lactamase-producing Enterobacterales bacteria cause severe hard-to-treat infections. Currently, they are spreading beyond hospitals and becoming a serious global health concern. This study investigated the prevalence and molecular characterization of extended-spectrum β-lactamase and AmpC-type β-lactamase-producing Enterobacterales (ESBL-PE, AmpC-PE) in wastewater from livestock and poultry slaughterhouses in Ardabil, Iran. A total of 80 Enterobacterales bacteria belonging to 9 species were identified. Among the isolates, Escherichia coli (n = 21/80; 26.2%) and Citrobacter spp. (n = 18/80; 22.5%) exhibited the highest frequency. Overall, 18.7% (n = 15/80) and 2.5% (n = 2/80) of Enterobacterales were found to be ESBL and AmpC producers, respectively. The most common ESBL producer isolates were E. coli (n = 9/21; 42.8%) and Klebsiella pneumoniae (n = 6/7; 85.7%). All AmpC-PE isolates belonged to E. coli strains (n = 2/21; 9.5%). In this study, 80% of ESBL-PE and 100% of AmpC-PE isolates were recovered from poultry slaughterhouse wastewater. All ESBL-PE and AmpC-PE isolates were multidrug-resistant. In total, 93.3% of ESBL-PE isolates harbored the blaCTX-M gene, with the blaCTX-M-15 being the most common subgroup. The emergence of ESBL-PE and AmpC-PE in wastewater of food-producing animals allows for zoonotic transmission to humans through contaminated food products and contaminations of the environment.

Antibiotic Resistance among Patients with Urinary Tract Infections in Kandahar, Afghanistan

Background

Antimicrobial resistance is a global public health threat. Highest burden of resistance is reported from low- and middle-income countries.

Objectives

To investigate and report the current scenario of increased antibiotic resistance of uropathogens among symptomatic urinary tract infection patients in Kandahar, Afghanistan.

Methods

From January 2018 to December 2021, this retrospective study was carried out at two main hospitals in Kandahar City, Afghanistan. Here, culture and sensitivity profiles of uropathogens were studied among symptomatic Bacteriuria in the presence of genitourinary symptoms (i.e., dysuria, suprapubic pain or tenderness, frequency, or urgency) (UTI) patients.

Results

Among urine samples of 1589 patients, 1047 (65.9%) were culture positive and included in this study. Most of these patients (626/1047 [59.8%]) were females, with majority (818 [78.1%]) having age between 19 and 39 years. Gram-negative bacteria were the most prevalent (840/1047 [80.2%]), with E. coli (653/1047 [62.4%]) as the most common isolated uropathogen. Overall gram-negative bacteria had higher resistance against commonly used antibiotics of cotrimoxazole (62.8%), ciprofloxacin (56.0%), levofloxacin (47.5%), cefixime (44.5%), fosfomycin (41.5%), and even ceftriaxone (48.3%).

Conclusions

Kandahar province has higher resistance rates against commonly used empirical antibiotics like norfloxacin, ciprofloxacin, levofloxacin, and cefixime. Nitrofurantoin should be used as the first-line antibiotic in treating UTI patients. Public health authorities should make strict regulations and policies to reduce irrational use, inappropriate prescription, and over-the-counter availability of antibiotics in Kandahar.

High Prevalence of Antimicrobial Resistance and Integron Gene Cassettes in Multi-Drug-Resistant Klebsiella pneumoniae Isolates From Captive Giant Pandas (Ailuropoda melanoleuca)

Multi-drug-resistant Klebsiella pneumoniae (MDR K. pneumonia) is increasingly being reported with corresponding increase in morbidity and mortality all over the world. However, limited information is available concerning MDR K. pneumonia in giant pandas. The objective of this study was to grasp the drug resistance profile of MDR K. pneumonia isolated from giant pandas. A total of 182 K. pneumoniae isolates were collected from fresh feces of 94 captive giant pandas of different ages and sex and separated by season. We performed a standard disk diffusion antimicrobial susceptibility test with the isolates and further evaluated the antibiotic resistance genes (ARGs) of multi-drug-resistant strains by high-throughput quantitative PCR. In addition, we then analyzed mobile genetic elements (MGEs), integron gene cassettes, and the multi-locus sequence typing of multi-drug-resistant strains by PCR. Antimicrobial susceptibility testing results demonstrated that a total of 30 (16.5%) K. pneumoniae isolates showed multiple drug resistances. The thirty MDR K. pneumonia isolates were mainly resistant to amoxicillin (100.0%), doxycycline (86.7%), chloramphenicol (60.0%), compound trimethoprim (60.0%) and trimethoprim (56.7%). Fifty different types of antibiotic resistance genes were found, which included a total of 671 antibiotic resistance genes, in the 30 multi-drug-resistant isolates. The top ten resistance genes were: vanTC-02, aacC, blaCTX-M-04, blaSHV-01, blaSHV-02, ampC-04, blaOXY, tetD, blaTEM and tetA-02. Thirteen mobile genetic elements were detected, of which IS26 (96.67%) and intI1 (96.67%) had the highest frequency. The thirty MDR K. pneumonia isolates were negative for the traA, traF, tnsA, IS1133, ISpa7, ISkpn6, intI2 and intI3 genes. Moreover, a further investigation of integrons revealed that two types of specific gene cassettes (dfrA12 + orfF + aadA2 and dfrA12 + orfF) were identified in class 1 integrons. Multi-locus sequence typing results showed that 22 STs in the thirty MDR K. pneumonia isolates were identified, the main type was ST37 (5/30). Our results illustrate that effective surveillance and strict biosecurity strategies should be taken to prevent the spread of multi-drug-resistant bacteria, and monitor the emergence of mobile genetic elements and integrons.

Epidemiologic and molecular characterization of β-lactamase-producing multidrug-resistant uropathogenic Escherichia coli isolated from asymptomatic hospitalized patients

Uropathogenic Escherichia coli (UPECs) are the predominant cause of asymptomatic bacteriuria (ABU) and symptomatic UTI. In this study, multidrug-resistant (MDR) ABU-UPECs from hospitalized patients of Kolkata, India, were characterized with respect to their ESBL phenotype, acquisition of β-lactamase genes, mobile genetic elements (MGEs), phylotype property, ERIC-PCR profile, sequence types (STs), clonal complexes (CCs) and evolutionary and quantitative relationships and compared to the symptomatic ones to understand their epidemiology and evolutionary origin. Statistically significant incidence of ESBL producers, β-lactamase genes, MGEs and novel phylotype property (NPP) among ABU-UPECs similar to the symptomatic ones indicated the probable incidence of chromosomal plasticity on resistance gene acquisition through MGEs due to indiscriminate drug usage. ERIC-PCR typing and MLST analysis showed clonal heterogeneity and predominance of ST940 (CC448) among asymptomatic isolates akin to symptomatic ones along with the evidence of zoonotic transmissions. Minimum spanning tree analysis showed a close association between ABU-UPEC with known and unidentified STs having NPPs with isolates that belonged to phylogroups clade I, D, and B2. This is the first study that reported the occurrence of MGEs and NPPs among ABU-UPECs with the predominance of ESBL production which displayed the deleterious effect of MDR among this pathogen demanding alternative therapeutic interventions. Moreover, this study for the first time attempted to introduce a new approach to ascertain the phylotype property of unassigned UPECs. Withal, increased recognition, proper understanding and characterization of ABU-UPECs with the implementation of appropriate therapeutic measures against them when necessary are the need of the era which otherwise might lead to serious complications in the vulnerable population.

Circulation of oxytetracycline- and ciprofloxacin-resistant commensal Escherichia coli strains in broiler chickens and farm environments, Bangladesh

Background and Aim:

The emergence of antimicrobial resistance (AMR) in commensal organism, such as Escherichia coli of food animals, is an alarming issue for global health. It increases the possibility of transmitting AMR determinant(s) to human bacterial pathogens by transferable genetic materials, particularly by plasmids. Hence, it is important to know which resistant genes are being carried by commensal organisms in food chain in a country and their level of temporal loads. As a result, pre-emptive measures can be advocated with an aim to reduce their risks in their primary source of circulation which consequently would benefit the public health.

Materials and Methods:

Commensal E. coli strains from broiler chickens on randomly selected 30 farms and the farm environments were examined for the frequencies of isolation of resistant strains to oxytetracycline and ciprofloxacin. Five birds were randomly selected from each farm to collect cloacal swab samples (total of 150 samples). Furthermore, a total of 150 environmental samples comprising one each from feed, water, soil, litter, and litter damping site of each farm were screened for the isolation of commensal E. coli strains. Strains thus obtained were initially tested for their resistance to oxytetracycline and ciprofloxacin by Kirby–Bauer disk diffusion method. Oxytetracycline-resistant strains were further screened for the presence of resistance determining genes, namely, tetA, tetB, and tetC by uniplex polymerase chain reactions. Risks associated with the isolation frequency of oxytetracycline- and ciprofloxacin-resistant E. coli were also assessed by univariable logistic regression analysis.

Results:

The results revealed that all E. coli isolates, regardless of the source of origin, were resistant to oxytetracycline, while 78.4% (95% confidence interval [CI] 69.1-85.5%) showed resistance to ciprofloxacin. All the randomly selected (20) oxytetracycline-resistant strains harbored the tetA gene, whereas tetB and tetC were reported in three and two isolates, respectively. After univariable analysis, only one variable, that is, strain 1 of broiler chickens compared to two other strains was found to be positively associated with the isolation of ciprofloxacin-resistant E. coli (odds ratio 12.75 [95% CI 1.0-157.1], p=0.047).

Conclusion:

Resistance emerged against oxytetracycline and ciprofloxacin in commensal E. coli strains circulating in live poultry and farm environments in Bangladesh seems to be very high. Thus, human infection with drug-resistant E. coli strains through food chain will critically compromise the therapeutic measures currently available.

High prevalence of multi-drug resistances and diversity of mobile genetic elements in Escherichia coli isolates from captive giant pandas

The purpose of this study was to characterize the antimicrobial resistance produced by mobile genetic elements and integron gene cassettes in Escherichia coli isolated from the feces of captive giant pandas. We performed a standard disk diffusion antimicrobial susceptibility test with 84 E. coli isolates and further evaluated the mobile genetic elements and integron gene cassettes. The antimicrobial susceptibility test demonstrated that 43.37% (36/84) of the isolates showed multiple drug resistances. The E. coli isolates mainly showed resistance to aztreonam (86.90%, 73/84) and amoxicillin/clavulanic acid (80.95%, 68/84). The most frequently observed resistance patterns were ampicillin/amoxicillin-clavulanic acid (13.10%, n = 11), and doxycycline/amoxicillin-clavulanic acid (4.76%, n = 4). Further analyses detected 11 mobile genetic elements, of which merA (54/84, 64.30%) had the highest frequency. All isolates were negative for intI3, traA, tnpU, traF, tnp513, tnsA, ISkpn7, ISpa7, ISkpn6, and ISCR1. We further analyzed antimicrobial resistance-related integrons among 30 E. coli isolates (the 27 intI1-positive isolates and the 3 intI2-positive isolates); six gene cassette profiles (dfrA17+aadA5, aadA2, dfrA12+aadA2, dfrA1+aadA1, dfrA1, and aadA1) were identified in the 27 intI1-positive isolates, but not in the three intI2-positive ones. Our study sheds light on the prevalence of multiple drug resistances and the diversity of mobile genetic elements in E. coli isolates, and highlights the necessity to monitor antibiotic resistance in more E. coli strains from captive giant pandas.

An Intelligent DNA Nanorobot with in Vitro Enhanced Protein Lysosomal Degradation of HER2

DNA nanorobots have emerged as new tools for nanomedicine with the potential to ameliorate the delivery and anticancer efficacy of various drugs. DNA nanostructures have been considered one of the most promising nanocarriers. In the present study, we report a DNA framework-based intelligent DNA nanorobot for selective lysosomal degradation of tumor-specific proteins on cancer cells. We site-specifically anchored an anti-HER2 aptamer (HApt) on a tetrahedral framework nucleic acid (tFNA). This DNA nanorobot (HApt-tFNA) could target HER2-positive breast cancer cells and specifically induce the lysosomal degradation of the membrane protein HER2. An injection of the DNA nanorobot into a mouse model revealed that the presence of tFNA enhanced the stability and prolonged the blood circulation time of HApt, and HApt-tFNA could therefore drive HER2 into lysosomal degradation with a higher efficiency. The formation of the HER2-HApt-tFNA complexes resulted in the HER2-mediated endocytosis and digestion in lysosomes, which effectively reduced the amount of HER2 on the cell surfaces. An increased HER2 digestion through HApt-tFNA further induced cell apoptosis and arrested cell growth. Hence, this novel DNA nanorobot sheds new light on targeted protein degradation for precision breast cancer therapy.

Molecular Characterization of Multidrug Resistant Strains of Acinetobacter baumannii Isolated from Intensive Care Units in West of Iran

INTRODUCTION

According to the results of various studies using phenotypic methods, the prevalence of Multidrug Resistant (MDR) Acinetobacter baumannii (A. baumannii) isolates has been increasing worldwide. Pulsed-Field Gel Electrophoresis (PFGE) technique is known as the gold standard method to determine clonal characterization of bacterial species, especially A. baumannii.

AIM

To determine the clonal relatedness and investigate the prevalence of integron classes 1 and 2 and genes encoding OXA-23 and 24 in A.baumanii isolates.

MATERIALS AND METHODS

A cross-sectional study was conducted from November 2011 to January 2013. A total of 140 A.baumannii isolates collected from three hospitals of Kermanshah were considered out of which 75 ICU isolates were included in this study. Antibiotics susceptibility test was done by disk diffusion method. Polymerase Chain Reaction (PCR) was performed in order to detect class 1 and 2 integrons and bla_OXA-23-like, bla_OXA-24-like genes. Isolates identified as MDR from a total of 75 Intensive Care Units (ICU) strains were subjected to genotyping for clonal relatedness.

RESULTS

A total of 37 isolates among 75 ICU isolates were identified as MDR. The maximum drug resistance was observed against ceftriaxone, mezlocycline, cefotaxime, piperacilin, ciprofloxacin and imipenem. Frequency of Class 1 and Class 2 Integrons, bla_OXA-23-like and bla_OXA-24-like genes were 33(44%), 27(36%), 60(80%) and 14(18.6%) respectively. Four clusters with high level of similarity were obtained showing homogeneity among MDR isolates.

CONCLUSION

Significant correlation between presence of integrons and resistance to different classes of antibiotic was observed in this study. Monitoring of drug resistance using gene integrase PCR and bla_OXA gene by cluster analysis is very important to plan specific infection control measures due to MDR A. baumannii.

Lysosome Inhibitors Enhance the Chemotherapeutic Activity of Doxorubicin in HepG2 Cells

The lysosome inhibitors bafilomycin A1 and chloroquine have both lysosomotropic properties and autophagy inhibition ability, and are promising clinical agents to be used in combination with anticancer drugs. In order to investigate this combination effect, HepG2 cells were treated with bafilomycin A1, chloroquine, or/and doxorubicin, and their proliferative ability, induction of apoptosis, and the changes of lysosomal membrane permeabilization and mitochondrial membrane potential were studied. The results demonstrate that treatment with bafilomycin A1 or chloroquine alone at a relatively low concentration promotes the inhibitory effect of doxorubicin on cell growth and apoptosis. Further studies reveal that bafilomycin A1 and chloroquine promote lysosomal membrane permeabilization and the reduction of mitochondrial membrane potential induced by doxorubicin. Our findings suggest that bafilomycin A1 and chloroquine potentiate the anticancer effect of doxorubicin in hepatic cancer cells and that supplementation of conventional chemotherapy with lysosome inhibitors may provide a more efficient anticancer therapy.