Antimicrobial Drug Resistance Research Articles

Impact of Chronic Tetracycline Exposure on Human Intestinal Microbiota in a Continuous Flow Bioreactor Model.

Studying potential dietary exposure to antimicrobial drug residues via meat and dairy products is essential to ensure human health and consumer safety. When studying how antimicrobial residues in food impact the development of antimicrobial drug resistance and disrupt normal bacteria community structure in the intestine, there are diverse methodological challenges to overcome. In this study, traditional cultures and molecular analysis techniques were used to determine the effects of tetracycline at chronic subinhibitory exposure levels on human intestinal microbiota using an in vitro continuous flow bioreactor. Six bioreactor culture vessels containing human fecal suspensions were maintained at 37 °C for 7 days. After a steady state was achieved, the suspensions were dosed with 0, 0.015, 0.15, 1.5, 15, or 150 µg/mL tetracycline, respectively. Exposure to 150 µg/mL tetracycline resulted in a decrease of total anaerobic bacteria from 1.9 × 107 ± 0.3 × 107 down to 2 × 106 ± 0.8 × 106 CFU/mL. Dose-dependent effects of tetracycline were noted for perturbations of tetB and tetD gene expression and changes in acetate and propionate concentrations. Although no-observed-adverse-effect concentrations differed, depending on the traditional cultures and the molecular analysis techniques used, this in vitro continuous flow bioreactor study contributes to the knowledge base regarding the impact of chronic exposure of tetracycline on human intestinal microbiota.

DESIGN, INSILICO SCREENING, MOLECULAR DOCKING, SYNTHESIS AND BIOLOGICAL EVALUATION OF BENZO-FUSED FIVE MEMBERED NITROGEN CONTAINING HETEROCYCLE AGAINST DNA GYRASE SUBUNIT B AS POTENTIAL ANTIMICROBIAL AGENT

Because of its function in DNA replication, DNA gyrase subunit B (1KZN) is a promising target for antimicrobial drug development. There is an urgent requirement for the designing and improvement of novel antimicrobial drugs due to the rapid development of antimicrobial drug resistance. The aim of this study is to use molecular docking to design, synthesise, and identify benzo-fused five-membered nitrogen containing heterocycle against DNA gyrase subunit B (1KZN). Using an effective procedure, 2-(1H-1,2,3-Benzotriazol-1-yl)-N-substituted acetamide was synthesised based on the literature review. The antimicrobial activity of all synthesised compounds was tested against four different organisms: E. coli, P. aeruginosa, S. aureus, and Candida albicans. The compound binds to the active site of DNA gyrase subunit B (1KZN) in a docking study, indicating that it may have antimicrobial activity. The compounds BT4 and BT6 have the antimicrobial capacity, according to the findings of this report. BT3 has the ability to be an antibacterial agent for Staphylococcus aureus.

In vitro and in silico analysis of Thymus serpyllum essential oil as bioactivity enhancer of antibacterial and antifungal agents

Wild thyme (Thymus serpyllum L.) of family Laminaceae is an unexplored perennial medicinal shrub. Aerial part of this plant is traditionally used for the treatment of respiratory and gastrointestinal problems. The current study was designed to evaluate the GC-MS, antimicrobial and synergistic potential of T. serpyllum essential oil (TEO). Chemical characterization of TEO showed the presence of thymol (15.79%), Phenol, 2-(1,1-dimethylethyl) (11.55%), o-Cymene (10.96%) as major phytocompounds. Antimicrobial activity of TEO in terms zone of inhibition (ZOI) varied from 13.66 ± 0.58 mm to 33.66 ± 1.52 mm, while, thymol (10%, v/v) showed ZOI ranged from 15.5 ± 0.5 mm to 26.33 ± 2.08 mm against tested bacterial and fungal species. MIC of TEO was 0.039% to 0.078% against tested bacterial and fungal species, whereas, thymol showed 1.25% to 2.5% MIC against tested bacterial and fungal species. Different combinations of TEO (2MIC to ½MIC) and thymol (2MIC to ½MIC) with antibacterial and antifungal antibiotics (2MIC to ½MIC) were found to increase the efficacy of antibiotics by 4-130 folds against bacterial and fungal pathogens. Molecular docking showed the good binding of thymol with both bacterial and fungal targets. Whereas MD simulation showed the stability of thymol complexed with target proteins over 100 ns time scale. Thymol also fulfills the Lipinski rule and showed characteristics similar to that of drugs. Therefore, it can be concluded from the present study that TEO and its major phytocompound, thymol can act as a bioactivity enhancer of antibacterial and antifungal antibiotics and could be used as a potential candidate to fight against antimicrobial drug resistance. Communicated by Ramaswamy H. Sarma

Frequencies, sensitivity pattern and molecular characterization of bacterial isolates in blood in neonatal sepsis.

Objective: To determine frequency, molecular characterization and sensitivity of bacterial isolates against commonly used antibiotics in neonatal sepsis. Study Design: Cross Sectional study. Setting: Department of Pathology Sahara Medical College Narowal. Period: October 2019 to March 2020. Material & Methods: Neonates admitted in neonatal intensive care unit (NICU) of study institution having signs and symptoms of neonatal symptoms such as fever, irritability, seizures, anorexia and lethargy, were included in the study using consecutive sampling technique. Blood sample from all study patients taken and sent for culture to determine bacterial isolates and antibiotic sensitivity against commonly used antibiotics for neonatal sepsis. Bacterial isolates identification was done using standard bacteriological technique performed by modified Kirby & Bauer disc diffuse method as per Clinical and Laboratory standards institute (CLSI) guidelines. Results: Total 200 cases were studied having neonatal sepsis and admitted in NICU including 58% female and 42% male children. Bacterial growth occurred in 10.5% samples and in 89.5% samples no bacterial growth seen. There were 1% samples with gram positive and 9.5% samples with gram negative bacterial isolates. Klebsiella was the commonest organism isolated in 38.1% cases out of total positive isolates. There were 72.5% neonates having age 1-14 days and 27.5% neonates having age 15-28 days. Conclusion: Gram negative bacteria are common cause of neonatal sepsis, out of which Klebsiella is the commonest organism. Antimicrobial drug resistance in different infections is a serious emerging issue.

Does transcriptional heterogeneity facilitate the development of genetic drug resistance?

Non-genetic forms of antimicrobial (drug) resistance can result from cell-to-cell variability that is not encoded in the genetic material. Data from recent studies also suggest that non-genetic mechanisms can facilitate the development of genetic drug resistance. We speculate on how the interplay between non-genetic and genetic mechanisms may affect microbial adaptation and evolution during drug treatment. We argue that cellular heterogeneity arising from fluctuations in gene expression, epigenetic modifications, as well as genetic changes contribute to drug resistance at different timescales, and that the interplay between these mechanisms enhance pathogen resistance. Accordingly, developing a better understanding of the role of non-genetic mechanisms in drug resistance and how they interact with genetic mechanisms will enhance our ability to combat antimicrobial resistance. Also see the video abstract here: https://youtu.be/aefGpdh-bgU.

Use of a modified Burow's solution to treat canine otitis externa: A randomised comparative clinical study.

Given the increase in antimicrobial drug resistance of several pathogens that affect the ear, there is a need for alternative therapy for canine otitis externa (OE). We hypothesised that the efficacy of modified Burow's solution would be non-inferior to that of standard treatment with Surolan. The treatment success rate of a topical aluminum acetate 2% and betamethasone 0.1% (modified Burow's) otic solution was compared with that of a standard topical otic treatment of polymyxin B sulfate, prednisolone acetate and miconazole (Surolan) suspension in a prospective, open-label clinical trial. For 10 days, 142 dogs (232 ears) with OE were treated with modified Burow's solution or Surolan. The primary study endpoint was the cure rate at 10 days. Clinical efficacy was analysed as a secondary endpoint but without assessment for non-inferiority. The 10-day OE cure rate was 65% and 59% in the Burow's and Surolan groups, respectively. The modified Burow's solution was non-inferior to Surolan at a non-inferiority margin of -11.5% and was more clinically effective than Surolan in dogs with OE caused by yeast or bacteria. The results of this study demonstrate that modified Burow's solution is an effective treatment for OE in dogs.

An Early History of Phage Therapy in the United States: Is it Time to Reconsider?

Frederick William Twort and Felix d'Hérelle independently discovered bacteriophages in 1915 and 1917, respectively. This led to the early trials of using bacteriophages to treat infectious diseases worldwide. The earliest reported use of bacteriophages therapeutically in the United States was in 1922. With the subsequent discovery of antibiotics in the 1940s, and because of disappointing results of phage therapy in the next decade, use of bacteriophages as therapeutic agents declined in western countries. This paper addresses two questions in the field: what is the historical record of the successes and failures of phage therapy in the United States and, what led to abandoning phage therapy in the United States? We examined the literature from 1915 to 1965, and we present a numerical analysis of the papers published during that period. We report key historical factors leading to a decline in the use of phage therapy in the United States by the 1950s. Since bacteriophages were first used therapeutically, several changes have occurred: increased antimicrobial drug resistance and a better knowledge of the biology of bacteriophages are important examples. Early assessments leading to the rejection of phage therapy in the United States were perhaps appropriate. However, it is time to reconsider the role of bacteriophages in treatment of bacterial infections.

A 4-year Study on Antimicrobial Susceptibility Trends of Nosocomial Infections in a Mashhad Referral Hospital, Mashhad, Iran

Introduction:In the present study, we evaluated the 4-year antimicrobial resistance trends of several nosocomial pathogens during 2018-2021 in a reffereal Mashhad hospital, Mashhad, Iran. Methods:In this study, we reviewed the data of 70,234 clinical isolates were registred Infection Control Data of Ghaem Hospital, Mashhad, Iran. The antimicrobial susceptibility testing was performed using Kirby-Bauer disk diffusion method according to clinical and laboratory standard institute (CLSI) instructions to evaluate trends of antimicrobial resistance over the times. Results: There were identified (A. baumannii: n = 19,374; K. pneumonia n = 17,206; E. coli n = 23,777; S. epidermidis: n = 9,877). We did not find any significant difference in changes of antimicrobial trends over the time except in minor cases . However, The pattern of antimicrobial drug resistance was gradually differed except E. coli. Conclusion: our results suggested the overall antimicrobial resistance trends was remins the same level during 2018-2021. It seems that in accessibility and stop prescribing of antibiotics can lead to decreasing antibiotic resistance rate.

Metabolite Fingerprinting of Novel Streptomyces UK-238 from the Himalayan Forest

Aims: Characterization of antimicrobial metabolites of novel Streptomyces sp. UK-238. Background: Novel antimicrobial drug discovery is urgently needed due to emerging multi antimicrobial drug resistance among pathogens. Since many years, natural products have provided the basic skeletons for many therapeutic compounds including antibiotics. Bioprospection of un/under explored habitats and focussing on selective isolation of actinobacteria as a major reservoir of bio and chemodiversity has yielded good results. Objective: The main objectives of the study were the identification of UK-238 by 16S rDNA sequencing and antimicrobial metabolite fingerprinting of culture extracts. Methods: In the present study, a promising isolate, UK-238, has been screened for antimicrobial activity and metabolite fingerprinting from the Himalayan Thano Reserve forest. It was identified by 16S rDNA sequencing. Ethyl acetate extract was partially purified by column chromatography. The pooled active fractions were fingerprinted by GC-MS and compounds were tentatively identified by collated data analysis based on Similarity Index, observed Retention Index from Databases and calculated Retention Index. Results: UK-238 was identified as Streptomyces sp. with 98.4% similarity to S. niveiscabiei. It exhibited broad-spectrum antibacterial and antifungal activity. GC-MS analysis of active fractions of ethyl acetate extract showed the presence of eighteen novel antimicrobial compounds belonging to four major categories- alcohols, alkaloid, esters and peptide. Conclusion: The study confirms that bioprospection of underexplored habitats can elaborate novel bio and chemodiversity.

Native Spider Silk-Based Antimicrobial Hydrogels for Biomedical Applications.

Novel antimicrobial natural polymeric hybrid hydrogels based on hyaluronic acid (HA) and spider silk (Ss) were prepared using the chemical crosslinking method. The effects of the component ratios on the hydrogel characteristics were observed parallel to the primary physicochemical characterization of the hydrogels with scanning electron microscopic imaging, Fourier-transform infrared spectroscopy, and contact angle measurements, which confirmed the successful crosslinking, regular porous structure, exact composition, and hydrophilic properties of hyaluronic acid/spider silk-based hydrogels. Further characterizations of the hydrogels were performed with the swelling degree, enzymatic degradability, viscosity, conductivity, and shrinking ability tests. The hyaluronic acid/spider silk-based hydrogels do not show drastic cytotoxicity over human postnatal fibroblasts (HPF). Hydrogels show extraordinary antimicrobial ability on both gram-negative and gram-positive bacteria. These hydrogels could be an excellent alternative that aids in overcoming antimicrobial drug resistance, which is considered to be one of the major global problems in the biomedical industry. Hyaluronic acid/spider silk-based hydrogels are a promising material for collaborated antimicrobial and anti-inflammatory drug delivery systems for external use. The rheological properties of the hydrogels show shear-thinning properties, which suggest that the hydrogels could be applied in 3D printing, such as in the 3D printing of antimicrobial surgical meshes.

Lancefield classification and antimicrobial resistance of hemolytic streptococci isolated from bovine mastitis.

Streptococcal species are known to be responsible for bovine mastitis. The aim of the present study was to determine antimicrobial drug resistance patterns of hemolytic streptococci distributed according to Lancefield serogrouping. Streptococcus sp. strains were isolated from 124 bovine milk samples from 31 cows with subclinical or clinical mastitis submitted to Mehmet Akif Ersoy University Faculty of Veterinary Medicine, Department of Microbiology Laboratory in Burdur province, Turkey from January 2015 to January 2017. A total of 63 Streptococcus sp. were isolated and the most frequently obtained isolates were classified as Lancefield's serogroup B (84.13%), the remaining isolates as serogroup F (15.87%). Out of 63 isolates, 53 (84.13%) showed beta‑hemolytic activity whereas 10 (15.87%) alpha‑hemolytic activity. Antimicrobial resistance was assessed by disk diffusion test against the most common antibiotics used in the field. Among the 63 Streptococcus sp. tested, the highest antimicrobial resistance patterns were observed for neomycin (95.24%), trimethoprim sulphamethoxazole (87.30%) and gentamicin (69.84%). None of the isolates showed resistance to amoxicillin‑clavulanic acid, except for one serogroup F isolate. The resistance rates for the other antimicrobials ranged from 1.59% to 38.04%. A total of 50 isolates exibited multi‑drug resistance to ≥ 3 antimicrobial agents tested. Overall, our results suggested that there is an urgent need to enhance awareness among the dairy farmers in choosing the appropriate drug for treating mastitis.

Cracking the Challenge of Antimicrobial Drug Resistance with CRISPR/Cas9, Nanotechnology and Other Strategies in ESKAPE Pathogens.

Antimicrobial resistance is mushrooming as a silent pandemic. It is considered among the most common priority areas identified by both national and international agencies. The global development of multidrug-resistant strains now threatens public health care improvement by introducing antibiotics against infectious agents. These strains are the product of both continuous evolution and unchecked antimicrobial usage (AMU). The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are the leading cause of nosocomial infections throughout the world. Most of them are now multidrug-resistant, which pose significant challenges in clinical practice. Understanding these bacteria’s resistance mechanisms is crucial for developing novel antimicrobial agents or other alternative tools to fight against these pathogens. A mechanistic understanding of resistance in these pathogens would also help predict underlying or even unknown mechanisms of resistance of other emerging multidrug-resistant pathogens. Research and development to find better antibacterial drugs and research on tools like CRISPER-Cas9, vaccines, and nanoparticles for treatment of infections that can be further explored in the clinical practice health sector have recognized these alternatives as essential and highly effective tools to mitigate antimicrobial resistance. This review summarizes the known antimicrobial resistance mechanisms of ESKAPE pathogens and strategies for overcoming this resistance with an extensive overview of efforts made in this research area.

Complete Genome Sequence of an Antimicrobial-Producing Bacillus velezensis Sam8H1 Isolate from the Makgadikgadi Saltpans of Botswana

The global antimicrobial drug resistance crisis requires urgency in searching for more effective broad-spectrum antimicrobial drugs. Here, we present a complete circular genome sequence and a plasmid of an antimicrobial-producing isolate, Bacillus velezensis strain Sam8H1, from the Makgadikgadi saltpans in Botswana. Bioinformatic analyses revealed 12 putative secondary metabolite biosynthetic gene clusters important for genome-guided drug discovery studies.

Phenotypic characterization of antimicrobial drug resistance of Staphylococcus aureus and S. epidermidis strains isolated from various community infections in Oum El Bouaghi city, Algeria

Abstract. Rahmani A, Meradi L, Malawi K, Khanfouf F. 2021. Phenotypic characterization of antimicrobial drug resistance of Staphylococcus aureus and S. epidermidis strains isolated from various community infections in Oum El Bouaghi city, Algeria. Biodiversitas 22: 2665-2671. In Algeria most community infections caused by Staphylococcus epidermidis and Staphylococcus aureus present resistance to several antibiotics and induce therapeutic failures. The aim of this study is the characterization and the comparison of antimicrobial resistance of Staphylococcus strains isolated from community infection in Oum El Bouaghi city, Algeria. Species identification was realized by conventional biochemical tests and the determination of antibiotics susceptibility pattern was realized by using the agar disk diffusion method, according to the recommendations of the French Society for Microbiology (FSM, 2019). A total of 102 Staphylococci strains were obtained from clinical samples, with a frequency of isolation of 57,8% for S. epidermidis and 42,2% for S. aureus, both strains present a resistance for most used antibiotics, the higher resistance was found for oxacillin in both strains with 25,6% for S. aureus and 42,4% for S. epidermidis. Multidrug-Resistance (MDR) phenotype was detected in 37,3% of S. epidermidis and 14% in S. aureus strains. In Algeria, new control policies should be adopted to prevent the further spread of antimicrobial-resistant strains, especially in the community

Structural and biological investigation of biogenically synthesized titanium dioxide nanoparticles: Calcination and characterization.

The antimicrobial drug resistance is increasing with the passage of time due to wide and improper use of broad spectrum drugs and the demand of the new drug increases day by day. The present study was planned to encounter this problem by synthesizing titanium dioxide nanoparticles (TiO2 NPs) by an eco-friendly route using Cannabis sativa leaves extract. The synthesized TiO2 NPs were calcined at 100, 300, 600, and 900°C in a muffle furnace. The crystallographic parameters were studied by X-ray diffraction and the phase transition occurred above 600°C. The surface morphology of the synthesized samples was studied by transmission electron microscopy (TEM), and scanning electron microscopy (SEM) and the particle size was measured through the ImageJ software. The elemental composition and purity of all the samples were studied by performing energy dispersive X-ray (EDX). All the synthesized TiO2 NPs were tested for their antimicrobial effect against Gram-positive and Gram-negative bacteria using the agar well diffusion method. The activity was found higher against Gram-negative bacteria and compared to Gram-positive bacteria.

Incidence of multidrug resistant Salmonella spp. In local food products sold in Ado-Ekiti, southwestern Nigeria

Background: Contaminated foods of animal origin are the primary reservoirs for human non-typhoidal Salmonellae infections. Transmission of Salmonellae to humans typically occurs by ingesting meat, dairy products, and other foods contaminated by animal faeces from foods contaminated with Salmonellae. Aim: This work aimed at the detection and incidence of viable Salmonella in local food products sold and consumed in Ado – Ekiti. Methods: Typing by pulse-field gel electrophoresis (PFGE), polymerase chain reaction (PCR) detection of antimicrobial drug resistance genes, and antibiotic susceptibility testing were done. Results: Out 105 samples analyzed, Salmonella species was isolated in 77 with highest incidence (100%) observed in kunu, pork meat, egg roll, raw egg and chicken. The antimicrobial drug resistance patterns on the isolates showed that Salmonella species were resistant to cotrimoxazole (100%), chloramphenicol (100%), amoxicillin (100%), ampicillin (86%) and ofloxacin (57%) while decreased susceptibility to ciprofloxacin (100%), streptomycin (100%), gentamycin (86%) and pefloxacin (71%) was found. multidrug resistance was observed in about 77% of the isolates. With PFGE, a total of eighty- three (83) patterns were observed and thirty-six 36(43%) isolates had the 3 most common patterns. All isolates from kunu and pork meat contained qnrB2, 6 (86%) isolates from egg roll contained blaCMY-2’; 9 (75%) isolates from liquid egg and chicken each contained blaCMY-23’. The total isolate of 73% is an indication of high incidence of Salmonella spp. in food products obtained in Ado-Ekiti. Conclusion: This study showed antimicrobial drug resistance in low resource settings and urgent need for surveillance and control of this phenomenon is recommended.

Antimicrobial drug resistance of Escherichia coli strains isolated from urinary tract infection and raw beef meat in Oum El Bouaghi city of Algeria

Antimicrobial resistance, especially in Escherichia coli, represents one of the most important human and animal health-threatening issues worldwide. The aim of this study was the characterization and the comparison of Antimicro-bial drug resistance of Escherichia coli strains isolated from urinary tract in-fection (UTI) and food (raw beef meat) in Oum El Bouaghi city-Algeria. The determination of antibiotics susceptibility pattern was realized by using the agar disk diffusion method, according to the recommendations of the French Society for Microbiology (FSM, 2019). A total, 159 E. coli were obtained from both clinical and food samples, with a frequency of isolation of 100% from raw beef meat and 59% from UTI. ESBL phenotype was detected only in 17% of clinical isolates. Also, the results of this work reveal that there is a highly significant difference in antibiotic resistance between clinical and foodborne isolates except for gentamicin. This high prevalence is a warning sign to adopt new control policies to prevent the further spread of this antimicrobial resistance.

Human Pleural Fluid and Human Serum Albumin Modulate the Behavior of a Hypervirulent and Multidrug-Resistant (MDR) Acinetobacter baumannii Representative Strain.

Acinetobacter baumannii is a nosocomial pathogen capable of causing serious infections associated with high rates of morbidity and mortality. Due to its antimicrobial drug resistance profile, A. baumannii is categorized as an urgent priority pathogen by the Centers for Disease Control and Prevention in the United States and a priority group 1 critical microorganism by the World Health Organization. Understanding how A. baumannii adapts to different host environments may provide critical insights into strategically targeting this pathogen with novel antimicrobial and biological therapeutics. Exposure to human fluids was previously shown to alter the gene expression profile of a highly drug-susceptible A. baumannii strain A118 leading to persistence and survival of this pathogen. Herein, we explore the impact of human pleural fluid (HPF) and human serum albumin (HSA) on the gene expression profile of a highly multi-drug-resistant strain of A. baumannii AB5075. Differential expression was observed for ~30 genes, whose products are involved in quorum sensing, quorum quenching, iron acquisition, fatty acid metabolism, biofilm formation, secretion systems, and type IV pilus formation. Phenotypic and further transcriptomic analysis using quantitative RT-PCR confirmed RNA-seq data and demonstrated a distinctive role of HSA as the molecule involved in A. baumannii’s response.

Antimicrobial drug resistance profile of isolated bacteria in dogs and cats with urologic problems at Chiang Mai University Veterinary Teaching Hospital, Thailand (2012-2016).

The present study aimed to estimate the proportion of bacterial urinary tract infection (UTI) in dogs and cats, assess risks associated with bacterial UTI, and to determine bacterial isolates' antimicrobial susceptibility and resistance pattern from the urinary tract of dogs and cats with urologic problems. The medical records from animals visiting Chiang Mai University Small Animal Veterinary Teaching Hospital between January 2012 and December 2016 were reviewed. In total, 203 dogs and 49 cats with urinary tract diseases that had samples submitted for bacterial culture were identified;198 and 24 bacterial isolates were recovered from dogs' and cats' submitted samples, respectively. At least one episode of bacterial UTI was detected in 75.4% (95% CI: 69.4-81.3) of dogs and in 40.8% (95% CI: 26.6-55.1) of cats with UTI and submitted urine cultures. Of 242 submitted urinary samples from dogs and 60 urinary samples from cats, bacteria were identified in 74.0% (95% CI: 68.4-79.5) and 38.3% (95% CI: 26.0-50.6), respectively. The most common pathogen of bacteria positive cultured from dogs was Staphylococcus spp. (30.3%), followed by Escherichia coli (16.7%), and Proteus spp. (13.6%). For cats, the most common pathogen was Pseudomonas spp. (25.0%), followed by E.coli (20.8%) and Proteus spp. (16.7%). Staphylococcus spp. isolates from dogs and Proteus spp. isolates from cats were highly susceptible to Amoxicillin/clavulanic acid (AMC) at 88% and 75%, respectively. Of all isolated bacteria, 67.1% of the bacteria from dogs and 83.3% from cats were multidrug-resistant (MDR). The proportion of MDR-bacterial urinary tract infections in dogs and cats with urologic problems in this study was high. This observation raises concerns regarding the potential of zoonotic transmission of MDR-bacteria from these companion animals. The results suggested that AMC remains a good empirical drug for treating UTIs in dogs in this region.

English

Bacteria develop antimicrobial drug resistance through several mechanisms, the common one being the production of enzymes. As the number of antibiotics discovered is in notable numbers in the past few years, it is important to preserve high-end antibiotics for the treatment of multidrug-resistant organisms (MDROs) infections, by appropriate use of antibiotics. A study was conducted to record prevalence, phenotypic and genotypic characters of MDROs in our hospital, with reference to carbapenem resistance. 200 multidrug-resistant clinical isolates were collected in 6 months. Carbapenem-resistant organisms were detected phenotypically confirmed for the production of carbapenemases by modified Hodge test (MHT) and genotypic detection was done by a multiplex polymerase chain reaction (PCR) assay for the five most predominant carbapenemases (bla NDM-1, bla OXA-48 , bla VIM, bla IMP, bla KPC). The isolates consisted of E. coli (53 %) followed by K. pneumoniae (30 %), P. aeruginosa (13 %), and acinetobacter spp (4 %). Among these, 40 (20 %) isolates were carbapenem-resistant. Of these 40, 27 (67.5 %) showed an increase in zone size by the MHT, suggestive of metallo-beta-lactamase (MBL) mediated carbapenem resistance and about 32 (80 %) isolates were found to contain at least one carbapenemase gene. bla NDM-1 accounted for 37.5 % (12 / 32) of the isolates and was the most predominant one followed by bla OXA-48 [28 % (9 / 32)]. 22 % (7 / 32) of the isolates had one or more carbapenemase genes. Identifying the mechanisms of resistance of pathogens is important to implement strict infection prevention and control measures in the hospital to prevent the transmission of the resistant pathogens. KEY WORDS Multidrug-Resistant Bacteria, Bla NDM-1 Gene, Bla OXA-48 Gene, Carbapenem Resistance, Carbapenem Resistant Organisms.