qnrA Genes Research Articles

Characterization of Transferrable Mechanisms of Quinolone Resistance (TMQR) among Quinolone-resistant Escherichia coli and Klebsiella pneumoniae causing Urinary Tract Infection in Nepalese Children

BackgroundTransferrable mechanisms of quinolone resistance (TMQR) can lead to fluoroquinolone non-susceptibility in addition to chromosomal mechanisms. Some evidence suggests that fluoroquinolone resistance is increasing among the pediatric population. We sought to determine the occurrence of TMQR genes among quinolone-resistant E. coli and K. pneumoniae causing urinary tract infections among Nepalese outpatient children (< 18 years) and identify molecular characteristics of TMQR-harboring isolates.MethodsWe performed antimicrobial susceptibility testing, phenotypic extended-spectrum β-lactamase (ESBL) and modified carbapenem inactivation method tests, and investigated the presence of six TMQR genes (qnrA, qnrB, qnrS, aac(6’)-Ib-cr, oqxAB, qepA), three ESBL genes (blaCTX−M, blaTEM, blaSHV), and five carbapenemase genes (blaNDM, blaOXA−48, blaKPC, blaIMP, blaVIM). The quinolone resistance-determining region (QRDR) of gyrA and parC were sequenced for 35 TMQR-positive isolates.ResultsA total of 74/147 (50.3%) isolates were TMQR positive by multiplex PCR [aac(6’)-Ib-cr in 48 (32.7%), qnrB in 23 (15.7%), qnrS in 18 (12.3%), qnrA in 1 (0.7%), and oqxAB in 1 (0.7%) isolate]. The median ciprofloxacin minimum inhibitory concentration of TMQR-positive isolates (64 µg/mL) was two-fold higher than those without TMQR (32 µg/mL) (p = 0.004). Ser-83→Leu and Asp-87→Asn in GyrA and Ser-80→Ile in ParC were the most common QRDR mutations (23 of 35). In addition, there was a statistically significant association between TMQR and two β-lactamase genes; blaCTX−M (p = 0.037) and blaTEM (p = 0.000).ConclusionThis study suggests a high prevalence of TMQR among the quinolone-resistant E. coli and K. pneumoniae isolates causing urinary tract infection in children in this area of Nepal and an association with the carriage of ESBL gene. This is a challenge for the management of urinary infections in children. Comprehensive prospective surveillance of antimicrobial resistance in these common pathogens will be necessary to devise strategies to mitigate the emergence of further resistance.

Molecular characterization of PMQR carrying bacteriophages in effluent discharge samples of Azerbaijan hospitals.

Quinolones are one of the most widely used drugs in medicine. Resistance to this agent has been increased significantly among the nosocomial isolates. The objective of this research was to study generalized transduction, as a potential mechanism for plasmid-mediated quinolone resistance (PMQR) genes acquisition among hospital effluent isolates. Discharge samples from hospital effluent were taken from four medical centers in Azerbaijan. Resident phages were enriched against resident enterobacterial hosts using standard phage enrichment protocols. Polymerase chain reaction (PCR) was used to examine phage stocks and bacterial isolates for the presence of PMQR determinants. All positive bacterial isolates for target genes were subjected to transduction assays. Restriction fragment length polymorphism (RFLP) profiles were determined for cluster analysis. A total of 55 pure phage stocks were prepared from 42 effluents. A total of 95 non-duplicated Gram-negative bacteria were isolated. Thirty-two EcoRV-RFLP profiles were determined for the 40 Escherichia coli phage stocks. Twenty-six of 40 (65%) E. coli phages were positive for qnrB (n = 15), qnrD (n = 7), qnrA (n = 3), and qnrC (n = 2) genes. A total of 34 (35.7%) bacterial isolates were recognized to have any PMQR genes including qnrB (n = 23), qnrD (n = 8), qnrA (n = 5), and qnrC (n = 3) genes. Present research provided a strong evidence for potential role of generalized transduction in persistence and circulation of PMQR genes in health care settings of Azerbaijan.

Prevalence and mechanisms of ciprofloxacin resistance in Escherichia coli isolated from hospitalized patients, healthy carriers, and wastewaters in Iran

BackgroundThis study was aimed to evaluate the prevalence and molecular characteristics of ciprofloxacin resistance among 346 Escherichia coli isolates collected from clinical specimens (n = 82), healthy children (n = 176), municipal wastewater (n = 34), hospital wastewater (n = 33), poultry slaughterhouse wastewater (n = 12) and livestock (n = 9) slaughterhouse wastewater in Iran.MethodsCiprofloxacin minimum inhibitory concentration (MIC) was determined by agar dilution assay. Phylogroups and plasmid-mediated quinolone resistance (PMQR) genes were identified using PCR. Mutations in gyrA, gyrB, parC, and parE genes and amino acid alterations were screened through sequencing assay. The effect of efflux pump inhibitor (PAβN) on ciprofloxacin MICs in ciprofloxacin-resistant isolates was investigated using the microdilution method.ResultsIn total, 28.03% of E. coli isolates were phenotypically resistant to ciprofloxacin. Based on sources of isolation, 64.63%, 51.51%, 33.33%, 14.70%, 10.22% and 8.33% of isolates from clinical specimens, hospital wastewater, livestock wastewater, municipal wastewater, healthy children and poultry wastewater were ciprofloxacin-resistant, respectively. Eighty-one point eighty-one percent (Ser-83 → Leu + Asp-87 → Asn; 78.78% and Ser-83 → Leu only; 3.03% (of ciprofloxacin-resistant E. coli isolates showed missense mutation in GyrA subunit of DNA gyrase, while no amino-acid substitution was noted in the GyrB subunit. DNA sequence analyses of the ParC and ParE subunits of topoisomerase IV exhibited amino-acid changes in 30.30% (Ser-80 → Ile + Glu-84 → Val; 18.18%, Ser-80 → Ile only; 9.10% and Glu-84 → Val only; 3.03%0 (and 15.38% (Ser-458 → Ala) of ciprofloxacin-resistant E. coli isolates, respectively. The PMQR genes, aac(6')-Ib-cr, qnrS, qnrB, oqxA, oqxB, and qepA were detected in 43.29%, 74.22%, 9.27%, 14.43%, 30.92% and 1.03% of ciprofloxacin-resistant isolates, respectively. No isolate was found to be positive for qnrA and qnrD genes. In isolates harboring the OqxA/B efflux pump, the MIC of ciprofloxacin was reduced twofold in the presence of PAβN, as an efflux pump inhibitor. The phylogroups B2 (48.45%) and A (20.65%) were the most predominant groups identified in ciprofloxacin-resistant isolates.ConclusionsThis study proved the high incidence of ciprofloxacin-resistant E. coli isolates in both clinical and non-clinical settings in Iran. Chromosomal gene mutations and PMQR genes were identified in ciprofloxacin resistance among E. coli population.

Investigation of antibiotic resistance genotypic and phenotypic characteristics of marine aquaculture fish carried in the Dalian area of China.

Due to the long-term and irrational use of antibiotics for the prevention and control of bacterial diseases in aquaculture, antibiotic resistance genes have become a new source of pollution in aquatic products. Factors such as the spread of drug-resistant strains and the horizontal transfer of drug-resistant genes have led to multi-drug resistance in fish-infecting bacteria, which seriously affects the quality and safety of aquatic products. In this study, 50 samples of horse mackerel and puffer fish sold in Dalian aquatic products market and seafood supermarket were collected, and the phenotypic characteristics of the bacteria carried by the fish for drugs such as sulfonamides, amide alcohols, quinolones, aminoglycosides and tetracyclines were tested and analyzed, and the resistance genes carried by fish samples were detected by SYBG qPCR. Our statistical analyses demonstrated that the drug resistance phenotypes and genotypes of bacteria carried by mariculture horse mackerel and puffer fish in the Dalian area of China were complex, and the multi-drug resistance rate reached 80%. Among the examined antibiotics, the resistance rates to cotrimoxazole, tetracycline, chloramphenicol, ciprofloxacin, norfloxacin, levofloxacin, kanamycin, and florfenicol exceeded 50%, whereas the resistance rates to gentamicin and tobramycin were 26 and 16%, respectively. The detection rate of the drug resistance genes tetA, sul1, sul2, qnrA, qnrS, and floR exceeded 70% and all samples carried more than three drug resistance genes. The correlation analysis of drug resistance genes and drug resistance phenotypes showed that the detection of the drug resistance genes sul1, sul2, floR, and qnrD was correlated with the detection of drug resistance phenotypes (p < 0.01). However, the correlation between the resistance genes cmlA, cfr, tetA, qnrA, qnrS, and aac(6')-Ib-cr and the corresponding resistance phenotype was not significant (p > 0.05). In general, our findings indicated that the multi-drug resistance of bacteria carried by marine horse mackerel and puffer fish in the Dalian area was serious. From the perspective of drug resistance rate and drug resistance gene detection rate, the aminoglycosides gentamicin and tobramycin are still considered effective in controlling bacterial infection in marine fish in the study area. Collectively, our findings provide a scientific basis for the management of drug use in mariculture, which can prevent the transmission of drug resistance through the food chain and minimize the associated human health risks.

Molecular Detection of Plasmid-Mediated Quinolone Resistance Genes (qnrA and aac(6′)-Ib-cr) in Drug Resistant Escherichia coli, Sudan

Background: The quinolone group, a synthetic antimicrobial, is widely used worldwide to treat many diseases, including those caused by Gram-negative bacteria. Escherichia coli and others are among the bacteria that produce quinolone resistance genes (qnr) such as qnrA and aac(6′)-Ib-cr. &#x0D; Objective: The present study aimed to the isolate Escherichia coli from patients attending some Hospitals in Wad Medani city, identification of drug resistance patterns and detection of the frequency of quinolones resistance genes; qnrA and aac(6′)-Ib-cr among isolated strains.&#x0D; Methods: A cross-sectional descriptive, hospital-based study included 119 Escherichia coli strains was conducted. A designed questionnaire used for demographic data collection and the attitude toward antimicrobials usage. Clinical specimens were processed for aerobic bacterial isolation and identification. Antimicrobial sensitivity performed by Kirby Bauer disc diffusion technique according to the CLSI guidelines. Presence of qnrA and aac(6′)-Ib-cr genes was assessed by multiplex PCR.&#x0D; Results: Most strains of Escherichia coli originated from urine 53.8% (64/119) and wounds 42.9% (51/119) specimens. Meropenem had the best effect against tested strains with susceptibility of 85% (101/119). Multiplex PCR assay, using specific primers, demonstrated that 41.2% (49/119) and 37.8% (45/119) of isolated Escherichia coli possessed qnrA and aac(6′)-Ib-cr genes respectively.&#x0D; Conclusion: The high rate of qnrA and aac (6)-Ib-cr genes among Escherichia coli necessitate the usage of molecular tools in detecting the genetic determinants of drug resistance microorganisms in countries such as Sudan.

Occurrence and distribution of antibiotics and antibiotic resistance genes in the different croplands along the Yellow River shoreline

Many antibiotics and their related antibiotic resistance genes (ARGs) are found in agricultural soil, raising concerns for public and environmental health. As a result, it is crucial to examine the abundance of sulfonamides, fluoroquinolones, tetracyclines, macrolides, and β-lactam antibiotics and their corresponding ARGs in agricultural soils. We investigted the abundance of aadA, sul1, aac(6’)-Ib, tetX, tetA, ermB, mphB, qnrA, intI1, intI2, and ISCR1 genes and explore their relationships with antibiotics in rice, peach orchard, maize, peanut, and garlic croplands along the Yellow River in Zhongmu and Yuanyang, Henan Province. There was no significant difference across the five croplands (P > 0.05), however, the paddy field had the highest average concentration (>10 μg kg−1) of oxytetracycline, tetracycline, ciprofloxacin and norfloxacin antibiotics. The predominant ARGs were aadA, sul1, with the the highest number of ARGs and MGEs detected in paddy rice, followed by maize, peanut, garlic, and peach soils. Integrase gene intI1 was significantly greater than intI2 and ISCR1, which was positively linked with sul1, aadA, aac(6′)-Ib, tetA, tetX, and ermB genes (P < 0.05). According to redundancy analysis, antibiotics may accelerated the prevalence of ARGs. Redundancy analysis demonstrated that antibiotics contributed 78.7% of the total ARG variations. Notably, the concentration of oxytetracycline in all the croplands ranged from 10.33 to 14.42 μg kg−1, which had impacted the frequency of ermB, bla CTX-M, intI2, and mphB genes as demonstrated by RDA analysis. Results revealed that effective techniques are required to lower the prevalence of ARGs in the agroecosystems.

Comparison of Antibiotic Resistance Profiles of Salmonella Isolates from Retail Meats in Nanchang, China, in Two Periods.

Salmonella is one of the most important foodborne pathogens. In this article, a total of 160 Salmonella isolates recovered from retail meats in June-July 2018 (before COVID-19 outbreak) and December 2020-April 2021 (after COVID-19 outbreak) in Nanchang, China, were characterized for serotyping, antimicrobial susceptibility, and specific resistance gene screening. The prevalence of Salmonella Typhimurium increased from 5.4% in 2018 to 19.1% in 2021, and Salmonella Enteritidis increased from 3.3% in 2018 to 8.8% in 2021. Compared with those in June-July 2018, Salmonella isolates in December 2020-April 2021 demonstrated a significant increase in resistance to 13 tested antibiotics except for doxycycline and nitrofurantoin (p < 0.05). The Salmonella isolates in December 2020-April 2021 showed a higher presence of plasmid-mediated quinolone resistance genes (qnrA, qnrB, and qnrS), and mutations in the quinolone resistance-determining region (gyrA Asp87Asn, gyrA Asp87Tyr, parC Thr57Ser, and parC Ser80Ile). Whole-genome sequencing was used to analyze four polymyxin B-resistant strains. Some common mutation sites in eptC and micA were found in the four strains. Based on the data in this article, it indicated that antibiotic resistance was facilitated and more gene mutations related to quinolone resistance were developed.

Characteristics of Antibiotic-resistant E. coli Isolated from Perfume River in Hue City, Vietnam

Antibiotic resistant bacteria (ARB) in aquatic environments is attracting increasing attention. However, the spread of ARB along Perfume River in Hue City is poorly understood. This study aimed to phenotypically and genotypically characterize β-lactam- and fluoroquinolone-resistant Escherichia coli isolates from this river. Water samples were collected from the urban, rural, agricultural, and less-affected areas in March 2020. E. coli susceptibility to seven commonly employed antibiotics was analyzed using the disk diffusion method, and the antibiotic resistance genes (ARGs), qnrA, qnrB, qnrS, TEM, SHV, and CTX-M, were identified using polymerase chain reaction (PCR) and DNA sequencing. The antibiotic susceptibility patterns of E. coli revealed that the rate of amoxicillin resistance was the highest (60%). PCR assays and sequencing of 12 β-lactam-resistant E. coli isolates indicated the presence of blaTEM and blaCTX-M-15 in 58.3% and 16.7% of the isolates, respectively. Only one of four fluoroquinolon -resistant E. coli isolates harbored the qnrS, while qnrA or qnrB genes were not detected. These findings suggest that this water may be an essential source of transmissible ARGs in Hue City, which may have a detrimental impact on the people living in this area.

Prevalence of Antibiotic-Resistant Pathogenic Bacteria and Level of Antibiotic Residues in Hospital Effluents in Selangor, Malaysia: Protocol for a Cross-sectional Study.

Antimicrobial resistance (AMR) has emerged as a major global public health challenge due to the overuse and misuse of antibiotics for humans and animals. Hospitals are among the major users of antibiotics, thereby having a large contribution to AMR. The aim of this study is to determine the prevalence of antibiotic-resistant pathogenic bacteria and the level of antibiotic residues in the hospital effluents in Selangor, Malaysia. A cross-sectional study will be performed in the state of Selangor, Malaysia. Tertiary hospitals will be identified based on the inclusion and exclusion criteria. The methods are divided into three phases: sample collection, microbiological analysis, and chemical analysis. Microbiological analyses will include the isolation of bacteria from hospital effluents by culturing on selective media. Antibiotic sensitivity testing will be performed on the isolated bacteria against ceftriaxone, ciprofloxacin, meropenem, vancomycin, colistin, and piperacillin/tazobactam. The identification of bacteria will be confirmed using 16S RNA polymerase chain reaction (PCR) and multiplex PCR will be performed to detect resistance genes (ermB, mecA, blaNDM-L, blaCTX-M, blaOXA-48, blaSHV, VanA, VanB, VanC1, mcr-1, mcr-2, mcr-3, Intl1, Intl2, and qnrA). Finally, the level of antibiotic residues will be measured using ultrahigh-performance liquid chromatography. The expected outcomes will be the prevalence of antibiotic-resistant Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter (ESKAPE) bacterial species from the hospital effluents, the occurrence of antibiotic resistance genes (ARGs) from the isolated ESKAPE bacteria, and the level of antibiotic residues that may be detected from the effluent. Sampling has been conducted in three hospitals. Data analysis from one hospital showed that as of July 2022, 80% (8/10) of E. faecium isolates were resistant to vancomycin and 10% (1/10) were resistant to ciprofloxacin. Further analysis will be conducted to determine if the isolates harbor any ARGs and effluent samples are being analyzed to detect antibiotic residues. Sampling activities will be resumed after being suspended due to the COVID-19 pandemic and are scheduled to end by December 2022. This study will provide the first baseline information to elucidate the current status of AMR of highly pathogenic bacteria present in hospital effluents in Malaysia. DERR1-10.2196/39022.

Molecular identification and detection of some virulence and antibiotic genes in Pantoea spp. isolated from clinical samples

Introduction and Aim: Pantoea species, are Gram negative bacteria that belong to the family Erwiniaceae. These bacteria are opportunistic pathogens known to cause several clinical infections in humans. The purpose of current research was to study the prevalence and identification of Pantoea spp. based on 16S rRNA sequencing, as well as detect the presence of antibiotic resistance and virulence genes in samples isolated from clinical cases. Materials and Methods: For the identification of Pantoea spp., DNA extracted from isolates were subjected to 16s rRNA amplification by PCR. Pantoea isolates were assessed for the presence of virulence (EsaI and ompA), and antibiotic (bacA, oqxB, qnrA, and ermB) genes using specific primers. Results: Three new strains were recorded based on results of 16S rRNA sequencing. The virulence gene Esal was prevalent in all isolates (100%) tested while 15/16 (94%) of isolates had ompA genes. The antibiotic-resistant gene oqxB was found in all isolates (100%), followed by bacA (87.5%), qnrA (75%), and ermB (37%) genes. Conclusion: Pantoea spp isolated from clinical samples were seen to harbor virulence as well as antimicrobial genes indicating the isolates to be pathogenic.

Antibiotic use in infants within the first year of life is associated with the appearance of antibiotic-resistant genes in their feces.

Antibiotic resistance, an increasing challenge, is not only a national threat but also a global threat. Carriage of resistance genes is not limited to adults alone, various microbiota niches present in the body system of children have been found to harbor bacteria carrying resistant genes, especially, their gut microbiota. This study aims to identify selected antibiotic-resistant genes from the fecal samples of infants and the association of antibiotics use with the occurrence of resistant genes in the infant's gut. A total number of 172 metagenomic DNA samples previously extracted from stool samples of 28 Nigerian babies longitudinally within their first year of life were screened for the presence of ESBL genes (blaSHV, blaTEM, and blaCTX-M), PMQR genes (qnrA, qnrB, qnrS, qepA), ribosomal protection protein tetracycline resistance gene, (RPP) β-lactamase (blaZ), macrolide (ermA, ermB, mefA/E), aminoglycoside modifying enzymes gentR (aac(6')/aph(2″)) and dfrA genes by PCR. Nineteen (19) of the 28 babies used antibiotics during the study. The association between antibiotic use by the babies within the first year of life and occurrence of resistant genes were analyzed by Spearman rank correlation. One hundred and twenty-two (122) samples (71%) out of the 172 isolates had antibiotic-resistance genes. PMQR genes were absent in all the samples. Three isolates had blaTEM gene, nine isolates had blaSHV gene, six isolates had blaCTX-M gene and 19 isolates had dfrA gene, 31 samples had tet gene, 29 samples had mef gene, 27 samples had ermB gene, four samples had ermA gene, 13 samples had blaZ gene and 16 samples had aac gene. The babies whose samples had resistant genes used antibiotics in the same months the samples were collected. Interestingly, the 11 babies whose samples had the dfrA gene all used antibiotics in the same months their samples were collected but none of them used trimethoprim/sulfamethoxazole antibiotic. The overall correlation matrix of the babies showed a strong association between antibiotic use (AU) and antibiotic use presence of resistance genes (AUPRG) with a coefficient of 0.89. Antibiotic-resistant genes are present in the gut of infants and their occurrence is strongly connected with antibiotic use by infants.

Bacteriological Profile of Chronic Rhinosinusitis and Adenotonsillitis: Evaluating the Role of Biofilm Production and Multidrug Resistance.

There is significant evidence that the etiology of chronic otorhinolaryngology infections such as chronic rhinosinusitis, adenotonsillitis, and otitis media depends on biofilms. As biofilm-forming bacteria can be resistant to the immune system, antibiotics, and other treatments, biofilm infections are often chronic. To identify the genus and species of the clinical isolates obtained from the swabs collected from the patients with chronic infections of the nasal and paranasal sinus, nasopharynx, and oropharynx and to evaluate phenotypic and genotypic methods for the detection of biofilms and antimicrobial resistance among the isolated organisms. A total of 100 patients with chronic rhinosinusitis and adenotonsillitis participated in this study. Various clinical samples from the nasal cavity, nasopharynx, and oropharynx were obtained and subjected to microbiological analysis and biofilm-forming capacity by three methods: tube methods, Congo red staining, and microtiter plate method. The various specific genes were amplified by polymerase chain reaction. The amplified gene products were separated by gel electrophoresis. This was a prospective cohort study conducted on a total of 100 patients with chronic rhinosinusitis and adenotonsillitis. The age of the study participants was between 7 and 53years with a mean age of 29.22 ± 15.03. This study included 54 (54%) nasal tissue samples and 46 (46%) adenotonsillar tissue. The frequently cultured organisms are coagulase-negative staphylococci (17%), E. coli (10%), Citrobacter (10%), and Klebsiella (7%). Staphylococcus aureus (4), and Methicillin-resistant Staphylococcus aureus (3) produced strong biofilm. Acenobacter (3), Citrobacter (4), and E. coli (4) showed moderate biofilm production. Coagulase-negative Staphylococcus aureus (11), E. coli (6), and Klebsiella (7) showed weak biofilm formation. Citrobacter (6), and Coagulase negative Staphylococcus aureus (6) were negative for biofilm production. Staphylococcus aureus expressed mecA gene (3) and Panton-Valentine Leukocidin gene (2), Pseudomonas expressed mucA gene (2), Citrobacter expressed blaCARB-2 (4) qnrA gene (2), E. coli expressed bla SHV (2) and bla TEM1 gene (2) and Klebsiella expressed Kfu (2) and uge (1). Acenobacter was negative for blaIMP1, blaVIM2 genes. This study adds to the information on the common pathogens-forming biofilms in various nasal pathologies and adenotonsillitis. The knowledge that a particular organism has a higher biofilm-forming capacity will help to sensitize the physician that factors such as biofilms may be at play and take appropriate measures.

Resistance genes and plasmid profile of bacteria Isolated from selected water bodies in Owo Metropolis

Aquatic samples from three water bodies were collected following laid down procedures. The bacteria were isolated using, Eosin Methylene Blue agar (EMB), Mannitol salt agar (MSA), Thiosulfate-Citrate-Bile Salts-Sucrose (TCBS) Agar, Muller Hinton (MH). The isolates were subjected to colonial, morphological and biochemical characterization. Pathogenicity test was carried out on the isolates using blood agar to determine their hemolytic activities. Antibiotic resistance status was also investigated against standard antibiotics using the Kirby Bauer disk diffusion method and the multiple antibiotic resistance indices of the isolates were also determined. The plasmid profiles were determined and the resistance genes were identified using molecular means. The bacteria species isolated were Veillonella Spp, Vibrio orientalis and Micrococcus luteus. Veillonella Spp showed Beta hemolysis while Micrococcus luteus showed alpha hemolysis and Vibrio orientalis showed gamma hemolysis. Antibiotic susceptibility test showed all isolates to be antibiotic resistant to varying degrees and multiple antibiotic resistance indices (MARi) depending on their level of resistance. Veillonella. spp. had MARi of 0.3 while M. luteus and V. orietalis had MARi of 0.5. Plasmid profiling showed all isolates to have plasmids with bandwidth of 10,000 bp. Vibrio spp and Veillonella Spp were positive for beta lactamase genes (bla SHV). Only Vibrio was positive for resistance to aminoglycosides (aac(3)-IV). Vibrio orientalis and Micrococcus luteus were found to have the resistance genes for quinolones (qnrA gene) while all the isolates possess genes against the sulphonamides (sul1 gene) used. The result of this work establishes the antibiotic resistance status of bacteria isolated from aquatic habitat and suggests their important role in the spread of antimicrobial resistance AMR, and antibiotic resistance genes (ARGs)

Plasmid - Mediated Quinolone Resistance (PMQR) determinants in multidrug-resistant, non - ESBL- producing, non-typhoidal Salmonella species isolated from commercial laying chickens

ABSTRACT Cloacal swab samples were collected from 350 apparently healthy commercial layers in Oyo and Osun states, Nigeria. Nine fluoroquinolone-resistant Salmonella species belonging to serovar Infantis (n=4), Heidelberg (n=3), and Saintpaul (n=2) were isolated from the sampled birds. The isolates were multidrug resistant with Multiple Antibiotic Resistance Index (MAR) ranging from 0.15 to 0.54. There was high resistance to fluoroquinolones, with 88.9% resistance to pefloxacin and ofloxacin, 77.8% to nalidixic acid and ciprofloxacin. None of the isolates were ESBL positive. All the nine isolates did not carry qnrA gene; 11.1%, 22.2% and 88.9% possessed qnrB, qnrD and qnrS, respectively. This study isolated plasmid mediated fluoroquinolone resistant rare Salmonella serovars from commercial layers in Nigeria.

Detection of antimicrobial resistance genes in Lactobacillus spp. from poultry probiotic products and their horizontal transfer among Escherichia coli

The study was conducted to identify the antimicrobial resistance genes (ARGs) in Lactobacillus spp. from poultry probiotic products and their potential to spread among Escherichia coli. Lactobacillus spp. were isolated and identified from 35 poultry probiotic samples based on the cultural, biochemical, and molecular findings. All the isolates (n = 35) were screened for the presence of some ARGs such as β-lactamases encoding genes (blaTEM, blaCTXM-1, and blaCTXM-2), plasmid-mediated quinolone resistance gene (qnrA, qnrB, and qnrS), and tetracycline resistance genes (tetA and tetB). Five Lactobacillus spp. isolates from three brands were positive for one or more ARGs. The qnrS was detected in four isolates. The blaTEM and tetB were detected in two isolates. One isolate contained blaCTX-M-1, blaCTX-M-2, and tetA genes. Brand-wise analysis revealed that one isolate from Brand 4 contained blaTEM, blaCTX-M-1, blaCTX-M-2, qnrS, and tetA genes, one isolate from Brand 2 contained blaTEM gene, and three isolates from Brand 7 harbored qnrS gene. The co-culture of Lactobacillus spp. and E. coli resulted in the transmission of qnrS, CTX-M-1, and tetA from Lactobacillus spp. to E. coli. Results of antimicrobial susceptibility test revealed that the highest resistance was observed to cefepime and cefotaxime followed by penicillin G, oxacillin, cefuroxime, and ofloxacin. The findings of the present study indicate the potential risk of horizontal spread of antimicrobial resistance through probiotic bacteria among the poultry population. Therefore, it is very necessary to check for ARGs along with other attributes of probiotic bacteria to avoid the inclusion of resistant strains in probiotics.

Spread of blaCTX-M-9 and Other Clinically Relevant Resistance Genes, Such as mcr-9 and qnrA1, Driven by IncHI2-ST1 Plasmids in Clinical Isolates of Monophasic Salmonella enterica Serovar Typhimurium ST34

The monophasic 4,[5],12:i:-variant of Salmonella enterica serovar Typhimurium with sequence type ST34 has become one of the most prevalent non-typhoidal salmonellae worldwide. In the present study, we thoroughly characterized seven isolates of this variant detected in a Spanish hospital and selected based on cefotaxime resistance and cefoxitin susceptibility, mediated by blaCTX-M-9. For this, conventional microbiological techniques, together with whole genome sequencing performed with the Illumina platform, were applied. All selected isolates carried the resistance region RR or variants therein, and most also contained the SGI-4 genomic island. These chromosomal elements, typically associated with monophasic S. Typhimurium ST34, confer resistance to traditional antibiotics (ampicillin, streptomycin, sulfonamides, and tetracycline) and tolerance to heavy metals (mercury, silver, and copper). In addition, each isolate carried a large IncHI2-ST1 conjugative plasmid containing additional or redundant resistance genes. All harbored the blaCTX-M-9 gene responsible for cefotaxime resistance, whereas the qnrA1 gene mediating fluoroquinolone resistance was detected in two of the plasmids. These genes were embedded in ISCR1-bearing complex class 1 integrons, specifically In60-like and In36-like. The mcr-9 gene was present in all but one of the IncHI2-ST1 plasmids found in the analyzed isolates, which were nevertheless susceptible to colistin. Most of the resistance genes of plasmid origin clustered within a highly complex and variable region. The observed diversity results in a wide range of resistance phenotypes, enabling bacterial adaptation to selective pressure posed by the use of antimicrobials.

Occurrence of ciprofloxacin resistance, plasmid-mediated quinolone resistance genes and virulence factors in Salmonella enterica serovar Enteritidis isolated from broilers in Thailand isolated from broilers in Thailand

Salmonella Enteritidis is one of the most common serovars associated with gastroenteritis in humans. Fluoroquinolone resistance in non-typhoidal Salmonella including S. Enteritidis has increased globally and is considered as a threat to public health. In this study, we aimed to investigate the occurrence of ciprofloxacin resistance and plasmid-mediated quinolone resistance (PMQR) genes, and examine virulence gene profiles of 69 S. Enteritidis isolates recovered from 46 boot swab and 23 intestinal samples collected from 69 commercial intensive broiler farms in Thailand. Ciprofloxacin susceptibility of these isolates was determined using microbroth dilution method. PCR was used to detect 5 common PMQR genes (qnrA, qnrB, qnrS, aac(6')-Ib-cr and qepA) and 12 important virulence genes (agfA, invA, spaN, prgH, sitC, ssaQ, mgtC, sopB, sifA, tolC, cdtB and spvC). All S. Enteritidis showed reduced susceptibility to ciprofloxacin, with the MIC values of 0.125-0.50 µg/mL. However, these isolates did not carry PMQR genes investigated. The same virulence profile was observed among 69 S. Enteritidis isolates in which 11 virulence genes, except cdtB, were detected. The presence of virulence genes identified in invasive salmonellosis in the S. Enteritidis isolates with reduced susceptibility to ciprofloxacin could be of public health concerns. Our findings underline the need for constant monitoring of ciprofloxacin-resistant S. Enteritidis in poultry production chain to reduce public health risk.

Resistance Patterns of Frequently Applied Antimicrobials and Occurrence of Antibiotic Resistance Genes in Edwardsiella tarda Detected in Edwardsiellosis-Infected Tilapia Species of Fish Farms of Punjab in Pakistan.

Edwardsiella tarda is one of the most significant fish pathogens, causes edwardsiellosis in a variety of freshwater fish species, and its antibiotic resistance against multiple drugs has made it a health risk worldwide. In this study, we aimed to investigate the antibiotic resistance (ABR) genes of E. tarda and establish its antibiotic susceptibility. Thus, 540 fish (299 Oreochromis niloticus, 138 O.mossambicus, and 103 O. aureus) were collected randomly from twelve fish farms in three districts of Punjab in Pakistan. E. tarda was recovered from 147 fish showing symptoms of exophthalmia, hemorrhages, skin depigmentation, ascites, and bacteria-filled nodules in enlarged liver and kidney. Antimicrobial susceptibility testing proved chloramphenicol, ciprofloxacin, and streptomycin effective, but amoxicillin, erythromycin, and flumequine ineffective in controlling edwardsiellosis. Maximum occurrence of qnrA, blaTEM, and sul3 genes of E. tarda was detected in 45% in the liver, 58%, and 42% respectively in the intestine; 46.5%, 67.2%, and 55.9% respectively in O. niloticus; 24%, 36%, and 23% respectively in summer with respect to fish organs, species, and season, respectively. Motility, H2S, indole, methyl red, and glucose tests gave positive results. Overall, E. tarda infected 27.2% of fish, which ultimately caused 7.69% mortality. The Chi-squared test of independence showed a significant difference in the occurrence of ABR genes of E. tarda with respect to sampling sites. In conclusion, the misuse of antibacterial agents has led to the emergence of ABR genes in E. tarda, which in association with high temperatures cause multiple abnormalities in infected fish and ultimately resulting in massive mortality.

Occurrence of Quinolone-Resistance Genes in Ciprofloxacin-Resistant Salmonella Enterica Serotype Typhi Isolated form Blood Sample of Patients with Typhoid Fever

Salmonella is approved as a common foodborne pathogen, causing major health problems throughout the world particularly in low‐ and middle‐income countries. Low-level fluoroquinolone resistance is conferred by both chromosomal and plasmid-encoded resistance, this research was carried out look into the occurrence rate of qnrA,qnrB and qnrS genes in Salmonella enterica serotype Typhi Cipr ofloxacin-resistant insulate from blood samples of patients with typhoid fever. Fifteen Salmonella enterica serotype Typhi isolated previously from patients with typhoid fever were included in this study. All bacterial isolates were confirmed to have ciprofloxacin resistant by VITEK 2 microbial identification system; after plasmid DNA extraction; multiplex-PCR was done with primer sequences intended to plasmid-mediated quinolone-resistance genes which is qnrA, qnrB, and qnrS. In this study; it was 21 qur genes amongst 15 isolates. The qnrS gene was the commonest (10/21, 47.6%) followed by qnrA (6/21, 28.5%), whereas only 4 isolates were positive for qnrB (5/21, 23.8%). Some isolates had more than one qnr genes. So, Ciprofloxacin-resistant Salmonella typhi can have more than one gene at the same time; and the most occurrence rate in regards to qnr gene in this study was qnrS compared to qnrA and qnrB

Multidrug-resistant Salmonella strains from food animals as a potential source for human infection in Iran

This study aimed to determine the frequency and characterization of Salmonella isolates from food-producing animals and human diarrheal samples in Shiraz, Iran. Overall, 105 Salmonella isolates were obtained from chicken meat (70/100, 70.0%), beef (19/100, 19.0%), lamb (11/100, 11.0%), and human stool (5/295, 1.7%). S. Infantis (40.9%), S. Enteritidis (29.5%), and S. Paratyphi B (8.6%) were the most prevalent serotypes. Totally 59.1% of the isolates were multidrug-resistant. High resistance to nalidixic acid (67.6%), tetracycline (62.9%), and trimethoprim-sulfamethoxazole (42.3%) were observed. Mutations in the gyrA and parC genes were detected in nalidixic acid-resistant isolates from chicken meat and human stool. No qnrA, qnrB or qnrS genes were detected. The blaTEM and blaCMY-2 genes were detected in β-lactam-resistant isolates from beef and lamb. Despite the high genetic diversity of PFGE patterns, some isolates from different sources and times showed identical PFGE patterns suggesting specific Salmonella species circulate between various sources over time.