Antibiotic Resistance Phenotypes Research Articles

Phenotypic and Genotypic Antibiotic Resistance Patterns of Clinical Shigella Isolates from Tehran, Iran

Background: The emergence of multidrug-resistant (MDR) Shigella is a health concern in both developed and developing countries. The indiscriminate use of antibiotics without considering resistance patterns has led to the emergence of resistant strains. Objectives: This study aimed to investigate the phenotypic and genotypic patterns of antibiotic resistance and virulence gene distribution in Shigella isolates from patients in Tehran, Iran. Methods: In this cross-sectional study, 60 Shigella isolates were collected from patients referred to Milad Hospital and Pasargad Laboratory in Tehran. The isolates were gathered over four months, from February 2023 to June 2023. After biochemical and genetic confirmation of the isolates, the disk diffusion method was employed to determine antibiotic resistance patterns. The distribution of beta-lactamase genes (blaCTX-M1, blaCTX-M2, blaCTX-M8, blaSHV, blaTEM, and blaOXA) and virulence genes (ial, virF, invE, sigA, and pic) was investigated in Shigella isolates using the multiplex PCR method. SPSS statistical software version 22 was used for data analysis. Results: Thirty-six percent of isolates were found to be MDR. The highest rate of resistance was against tetracycline (90%) and ampicillin (80%). The lowest resistance rate was against azithromycin (1.9%) and amikacin (7.1%). The blaCTX-M1 and blaCTX-M8 genes were more prevalent, detected in 38.3% and 50% of the isolates, respectively. However, the blaSHV and blaCTX-M2 genes were not detected in any of the isolates. Additionally, 32% of the MDR isolates harbored both the blaCTX-M1 and blaCTX-M8 genes simultaneously. The distribution of virulence genes ial, virF, invE, sigA, and pic in the studied isolates was 28.3%, 85%, 68.3%, 81.7%, and 15%, respectively. Conclusions: The present study emphasizes the increasing trend of MDR Shigella isolates. Therefore, serious measures are needed to prevent the spread of resistant genes. Furthermore, the detection of virulence factors could help in controlling shigellosis, which is a significant global health issue.

Genomic analysis of multidrug-resistant Escherichia coli from Urban Environmental water sources in Accra, Ghana, Provides Insights into public health implications.

Wastewater discharge into the environment in resource-poor countries poses a threat to public health. Studies in this area within these countries are limited, and the use of high-throughput whole-genome sequencing technologies is lacking. Therefore, understanding of environmental impacts is inadequate. The present study investigated the antibiotic resistance profiles and diversity of beta-lactamases in Escherichia coli strains isolated from environmental water sources in Accra, Ghana. Microbiological analyses were conducted on wastewater samples from three hospitals, a sewage and wastewater treatment plant, and water samples from two urban surface water bodies. Confirmed isolates (N = 57) were selected for phenotypic antibiotic resistance profiles. Multi-drug-resistant isolates (n = 25) were genome sequenced using Illumina MiSeq sequencing technology and screened for sequence types, antibiotic resistance, virulence and beta-lactamase genes, and mobile genetic elements. Isolates were frequently resistant to ampicillin (63%), meropenem (47%), azithromycin (46%), and sulfamethoxazole-trimethoprim (42%). Twenty different sequence types (STs) were identified, including clinically relevant ones such as ST167 and ST21. Five isolates were assigned to novel STs: ST14531 (n = 2), ST14536, ST14537, and ST14538. The isolates belonged to phylogroups A (52%), B1 (44%), and B2 (4%) and carried β-lactamase (TEM-1B, TEM-1C, CTX-M-15, and blaDHA-1) and carbapenemase (OXA-1, OXA-181) resistance genes. Dominant plasmid replicons included Col440I (10.2%) and IncFIB (AP001918) (6.8%). Polluted urban environments in Accra are reservoirs for antibiotic-resistant bacteria, posing a substantial public health risk. The findings underscore the need for targeted public health interventions to mitigate the spread of antibiotic-resistant bacteria and protect public health.

Evaluation of fortimicin antibiotic combinations against MDR Pseudomonas aeruginosa and resistome analysis of a whole genome sequenced pan-drug resistant isolate

BackgroundMultidrug-resistant (MDR) P. aeruginosa is a rising public health concern, challenging the treatment of such a ubiquitous pathogen with monotherapeutic anti-pseudomonal agents. Worryingly, its genome plasticity contributes to the emergence of P. aeruginosa expressing different resistant phenotypes and is now responsible for notable epidemics within hospital settings. Considering this, we aimed to evaluate the synergistic combination of fortimicin with other traditional anti-pseudomonal agents and to analyze the resistome of pan-drug resistant (PDR) isolate.MethodsStandard methods were used for analyzing the antimicrobial susceptibility tests. The checkerboard technique was used for the in vitro assessment of fortimicin antibiotic combinations against 51 MDR P. aeruginosa and whole genome sequencing was used to determine the resistome of PDR isolate.ResultsOut of 51 MDR P. aeruginosa, the highest synergistic effect was recorded for a combination of fortimicin with β-lactam group as meropenem, ceftazidime, and aztreonam at 71%, 59% and 43%, respectively. Of note, 56.8%, 39.2%, and 37.2% of the tested MDR isolates that had synergistic effects were also resistant to meropenem, ceftazidime, and aztreonam, respectively. The highest additive effects were recorded for combining fortimicin with amikacin (69%) and cefepime (44%) against MDR P. aeruginosa. Resistome analysis of the PDR isolate reflected its association with the antibiotic resistance phenotype. It ensured the presence of a wide variety of antibiotic-resistant genes (β-lactamases, aminoglycosides modifying enzymes, and efflux pump), rendering the isolate resistant to all clinically relevant anti-pseudomonal agents.ConclusionFortimicin in combination with classical anti-pseudomonal agents had shown promising synergistic activity against MDR P. aeruginosa. Resistome profiling of PDR P. aeruginosa enhanced the rapid identification of antibiotic resistance genes that are likely linked to the appearance of this resistant phenotype and may pave the way to tackle antimicrobial resistance issues shortly.

Distribution and expression of the aac(6')-Im (aacA16) aminoglycoside resistance gene.

The aac(6')-Im (aacA16) amikacin, netilmicin and tobramycin resistance gene cassette had been circulating globally undetected for many years in a sublineage of Acinetobacter baumannii global clone 2. To identify sources for the aac(6')-Im fragment found in A. baumannii. MinION long-read sequencing and Unicycler hybrid assemblies were used to determine the genetic context of the aac(6')-Im gene. Quantitative reverse transcriptase PCR was used to measure expression. Among >60 000 non-Acinetobacter draft genomes in the MRSN collection, the aac(6')-Im gene was detected in Pseudomonas putida and Enterobacter hormaechei isolates recovered from patients in Thailand between 2016 and 2019. Genomes of multiply resistant P. putida MRSN365855 and E. hormaechei MRSN791417 were completed. The class 1 integron containing the aac(6')-Im cassette was in the chromosome in MRSN365855, and in an HI2 plasmid in MRSN791417. However, MRSN791417 was amikacin susceptible and the gene was not expressed due to loss of the Pc promoter of the integron. Further examples of aac(6')-Im in plasmids from or the chromosome of various Gram-negative species were found in the GenBank nucleotide database. The aac(6')-Im context in integrons in pMRSN791417-8 and a Klebsiella plasmid pAMR200031 shared similarities with the aac(6')-Im region of AbGRI2-Im islands in A. baumannii. In other cases, the cassette array including the aac(6')-Im cassette was different. The aac(6')-Im gene is widespread, being found so far in several different species and in several different gene cassette arrays. The lack of amikacin resistance in E. hormaechei highlights the importance of correlating resistance gene content and antibiotic resistance phenotype.

The Prevalence of Antibiotic Resistance Phenotypes and Genotypes in Multidrug-Resistant Bacterial Isolates from the Academic Hospital of Jaén, Spain.

The heterogenicity of antimicrobial resistance genes described in clinically significant bacterial isolates and their potential role in reducing the efficacy of classically effective antibiotics pose a major challenge for global healthcare, especially in infections caused by Gram-negative bacteria. We analyzed 112 multidrug-resistant (MDR) isolates from clinical samples in order to detect high resistance profiles, both phenotypically and genotypically, among four Gram-negative genera (Acinetobacter, Escherichia, Klebsiella, and Pseudomonas). We found that 9.8% of the total selected isolates were classified as extensively drug-resistant (XDR) (six isolates identified as A. baumannii and five among P. pneumoniae isolates). All other isolates were classified as MDR. Almost 100% of the isolates showed positive results for blaOXA-23 and blaNDM-1 genes among the A. baumannii samples, one resistance gene (blaCTX-M) among E. coli, and two genetic determinants (blaCTX-M and aac(6')-Ib) among Klebsiella. In contrast, P. aeruginosa showed just one high-frequency antibiotic resistance gene (dfrA), which was present in 68.42% of the isolates studied. We also describe positive associations between ampicillin and cefotaxime resistance in A. baumannii and the presence of blaVEB and blaGES genes, as well as between the aztreonam resistance phenotype and the presence of blaGES gene in E. coli. These data may be useful in achieving a better control of infection strategies and antibiotic management in clinical scenarios where these multidrug-resistant Gram-negative pathogens cause higher morbidity and mortality.

In vitro efficacy of combinations of antibiotics used in clinical practice on clinical isolates of Helicobacter pylori.

The main antibiotics used against Helicobacter pylori have been chosen empirically over time, with few preclinical studies to provide support. The rise in resistance to some of these antibiotics is prompting a reassessment of their use. This work aimed to evaluate the invitro efficacy of 2 × 2 combinations of the most widely used antibiotics against H. pylori. J99 reference strains and 19 clinical isolates of H. pylori with various antibiotic resistance phenotypes were used. Minimum inhibitory concentrations were carried out using the microdilution method in 96-well plates. The activity of 15 possible combinations of two antibiotics including amoxicillin, clarithromycin (CLA), levofloxacin, rifampicin, tetracycline, and metronidazole was determined for all strains by the checkerboard method. A mean fractional inhibitory concentration index (FICmean) was calculated for each combination and strain and the type of pharmacodynamic interaction was considered as synergic if FICmean ≤ 0.5, additive if 0.5 < FICmean ≤ 1, indifferent if 1 < FICmean < 4 or antagonistic if FICmean ≥ 4. Most of the 285 pharmacodynamic interactions tested with clinical strains were close to additivity (average FICmean = 0.89 [0.38-1.28]). No interaction was found to be antagonistic. When two antibiotics to which a strain was resistant were combined, the concentrations required to inhibit bacterial growth were higher than their respective breakpoints. The present results have shown that invitro, the different antibiotics used in therapeutics have additive effects. The addition of the effects of two antibiotics to which a strain was resistant was not sufficient to inhibit bacterial growth. In probabilistic treatment, the choice of antibiotics to combine should therefore be based on the local epidemiology of resistance, and on susceptibility testing in the case of CLA therapy, so that at least one antibiotic to which the strain is susceptible is used.

Physical quality and antibiotic susceptibility profile of &lt;i&gt;Escherichia coli&lt;/i&gt; isolates from roof-harvested rainwater: A microcosm study

Owing to the inadequate supply of potable water in rural settlements in developing countries, roof-harvested rainwater (RHRW) has been favoured as an alternative source of water supply. The present study investigated the physical characteristics and microbial quality of 10 RHRW samples collected from storage tanks in Ikwo community of Ebonyi State, Nigeria. Triplicate water sampling was performed over a 3-month sampling regime. Onsite determination of odour, colour, pH and temperature, and isolation and enumeration of Escherichia coli were done using standard procedures. The identity of the isolates was confirmed using molecular techniques, and the susceptibility of the isolates to 11 antibiotics was determined following the Kirby-Bauer disc diffusion assay. Multiple antibiotic resistance phenotypes and indices (MARPs and MARI) were equally determined. Our findings revealed that the RHRWs had unobjectionable odour and were colourless. Across the 3-month o sampling, the pH ranged from 6.9 to 7.8 while the temperature was between 24 °C and 29 C. While E. coli was absent in samples E (September), H (August and October) and J (August, September, and October), the highest E. coli count in August, September, and October was 37, 32, and 38 cfu/100 mL, respectively. The antibiotic susceptibility test on 40 E. coli isolates showed high resistance to ampicillin (100%), aztreonam (98%), cefotetan (97%), nitrofurantoin (90%), imipenem (83%), streptomycin (72%), and ertapenem (69%). Interestingly, the ighest MARP, 11 (AK/S/ETP/IMI/OFX/NOR/AMP/CTT/ATM/F/TE) (sample B), and the least, 4 (IMI/AMP/CTT/ATM) were recorded in samples B and D, respectively in September. MARI was from 0.42 to 1.00. The physical parameters conform with WHO standards, on the other hand, detection of E. coli poses risks of water-borne illness(es) and transmission of antimicrobial resistance. Hence stringent measures including proper treatment, sanitation and hygiene are advocated to safeguard the health of dwellers who depend on this water source for daily life activities.

A laboratory-based predictive pathway for the development of Neisseria gonorrhoeae high-level resistance to corallopyronin A, an inhibitor of bacterial RNA polymerase.

The continued emergence of multi-antibiotic-resistant strains of Neisseria gonorrhoeae necessitates the development of new antibiotics that are effective against this human pathogen. We previously described that the RNA polymerase-targeting antibiotic corallopyronin A (CorA) has potent activity against a large collection of clinical strains that express different antibiotic resistance phenotypes including when such gonococci are in a biofilm state. Herein, we tested whether a CorA-sensitive gonococcal strain could develop spontaneous resistance. Our finding that CorA resistance could only be achieved by a multi-step process involving over-expression of the MtrCDE efflux pump and single amino acid changes in RpoB and RpoC suggests that such resistance may be difficult for gonococci to evolve if this antibiotic is used in the future to treat gonorrheal infections that are refractory to cure by other antibiotics.

Virulence, antibiotic resistance phenotypes and molecular characterisation of Vibrio furnissii isolates from patients with diarrhoea.

Vibrio furnissii is an emerging human pathogen closely related to V. fluvialis that causes acute gastroenteritis. V. furnissii infection has been reported to be rarer than V. fluvialis, but a multi-drug resistance plasmid has recently been discovered in V. furnissii. During daily monitoring at a general hospital in Beijing, China, seven V. furnissii strains were collected from patients aged over 14 years who presented with acute diarrhoea between April and October 2018. Genome analysis and comparison were performed for virulence and antimicrobial resistance genes, plasmids and transposon islands, together with phylogenetic analysis. Antimicrobial resistance to 19 antibiotics was investigated using the microbroth dilution method. Virulence phenotypes were investigated based on type VI secretion system (T6SS) expression and using a bacterial killing assay and a haemolysin assay. Phylogenetic analysis based on single-nucleotide polymorphisms revealed a closer relationship between V. furnissii and V. fluvialis than between other Vibrio spp. The seven V. furnissii isolates were in different monophyletic clades in the phylogenetic tree, suggesting that the seven cases of gastroenteritis were independent. High resistance to cefazolin, tetracycline and streptomycin was found in the V. furnissii isolates at respective rates of 100.0%, 57.1% and 42.9%, and intermediate resistance to ampicillin/sulbactam and imipenem was observed at respective rates of 85.7% and 85.7%. Of the tested strains, VFBJ02 was resistant to both imipenem and meropenem, while VFBJ01, VFBJ02, VFBJ05 and VFBJ07 were multi-drug resistant. Transposon islands containing antibiotic resistance genes were found on the multi-drug resistance plasmid in VFBJ05. Such transposon islands also occurred in VFBJ07 but were located on the chromosome. The virulence-related genes T6SS, vfh, hupO, vfp and ilpA were widespread in V. furnissii. The results of the virulence phenotype assays demonstrated that our isolated V. furnissii strains encoded an activated T6SS and grew in large colonies with strong beta-haemolysis on blood agar. This study showed that diarrhoea associated with V. furnissii occurred sporadically and was more common than expected in the summer in Beijing, China. The antibiotic resistance of V. furnissii has unique characteristics compared with that of V. fluvialis. Fluoroquinolones and third-generation cephalosporins, such as ceftazidime and doxycycline, were effective at treating V. furnissii infection. Continua laboratory-based surveillance is needed for the prevention and control of V. furnissii infection, especially the dissemination of the antibiotic resistance genes in this pathogen.

Increased susceptibility to azithromycin of Pseudomonas aeruginosa biofilms using RPMI 1640 testing media.

Azithromycin (AZM) is efficient for treatment of chronic Pseudomonas aeruginosa biofilm lung infections, despite of resistance in conventional susceptibility testing. It has been shown that planktonic P. aeruginosa are more susceptible to AZM when tested in RPMI 1640 medium. The aim of the study was to test the susceptibility to AZM of P. aeruginosa biofilms in LB vs RPMI 1640 media. We investigated the effect of AZM on planktonic and biofilms of (WT) P. aeruginosa (PAO1), the hypermutable (ΔmutS) and the antibiotic-resistant phenotype(ΔnfxB) mutants. The effect of AZM on young and mature biofilms was investigated in the modified Calgary Biofilm Device by estimation of the minimal biofilm inhibitory concentration (MBIC). The AZM MBIC90 in LB/RPMI1640 on young biofilms treated for 24 h was 16/4 μg/mL for PAO1, 32/8 μg/mL for ΔmutS, and 256/16 μg/mL for ΔnfxB, while in mature biofilms was 256/2 μg/mL for PAO1 and ΔmutS and 16/1 μg/mL for ΔnfxB. The effect of AZM was improved when the treatment was prolonged to 72 h, supporting the intracellular accumulation of AZM. An increased susceptibility of P. aeruginosa biofilms to AZM was observed in RPMI 1640 than in LB medium. Our results might improve susceptibility testing and dosing of AZM for treatment of biofilm infections.

Monitoring of Klebsiella pneumoniae as one of the criteria of microecological characterization of a water body

Introduction. Representatives of the family Enterobacteriaceae are ubiquitous in the environment, causing severe, including opportunistic diseases in immunocompromised individuals. The occurrence of antibiotic-sensitive bacteria of the Klebsiella genus within the recreational zone of a water body is potent of posing an epidemiologic danger to the inhabitants of the settlement. &#x0D; Materials and Methods. Water samples from the surface aquifers of the Don and Temernik rivers of Rostov-on-Don served as the material for the study. The sensitivity of isolates of Kl. pneumoniae isolates to fourteen antibacterial preparations were investigated by disk-diffusion method in accordance with the requirements of MUK 4.2.1980-04 and EUCAST v. 13.0 (2023). 13.0 (2023). Carbapenemase genes VIM, IMP, NDM, KPC, OXA-48, NDM were determined using commercial diagnostic kits AmpliSense MDR MBL-FL, AmpliSense MDR KPC/OXA-48-FL, AmpliSense MDR Ab-OXA-FL.&#x0D; Results. In 2022, 247 isolates of Klebsiella pneumoniae were isolated in 14 biotopes of water bodies of Rostov-on-Don. Biotopes of epidemiological significance were identified with the presence of antibiotic resistance genes in 28 isolates isolated above and below the sewage discharge site (sampling point #1 and #5) and strains isolated from the mouth of the Temernik River (sampling point #14). Phenotype of multidrug-resistant (MDR) in point No. 1 possessed 22%, point No. 5 – 26.9%, point No. 14 – 26%; phenotype of extreme drug resistance (XDR) in point No. 1 possessed 11.1 %, point No. 5 – 15.3%, point No. 14 – 13%; phenotype of pan-drug-resistant (PDR) in point No. 1 did not possess, point No. 5 – 3.8%, point No. 14 – 4.3%.&#x0D; Limitations. A limitation of the study is related to the location of water sampling from the river. Don and R. Temernik on the territory of Rostov-on-Don, covering from March to November 2022. In this article, we limited ourselves to sanitary-bacteriological and molecular genetic analysis.&#x0D; Conclusion. The detection of PDR, XDR, and MDR antibiotic-resistant phenotypes of Klebsiella pneumoniae, as well as the detection of resistance genes, indicates to an increased risk of water-associated acute intestinal infections, especially in immunosuppressed individuals.

Overview of Proteus mirabilis pathogenicity and virulence. Insights into the role of metals.

Proteus mirabilis is a Gram-negative bacterium with exclusive molecular and biological features. It is a versatile pathogen acclaimed for its distinct urease production, swarming behavior, and rapid multicellular activity. Clinically, P. mirabilis is a frequent pathogen of the human urinary system where it causes urinary tract infections (UTIs) and catheter-associated urinary tract infections (CAUTIs). This review explores the epidemiology, risk factors, clinical manifestations, and treatment of P. mirabilis infections, emphasizing its association with UTIs. The bacterium's genome analysis revealed the presence of resistance genes against commonly used antibiotics, an antibiotic-resistant phenotype that poses a serious clinical challenge. Particularly, the emergence of extended-spectrum β-lactamases (ESBLs) and carbapenemases resistant P. mirabilis strains. On a molecular level, P. mirabilis possesses a wide array of virulence factors including the production of fimbriae, urease, hemolysins, metallophores, and biofilm formation. This review thoroughly tackles a substantial gap in understanding the role of metallophores in shaping the virulence factors of P. mirabilis virulence. Siderophores, iron metal chelating and transporting metallophores, particularly contribute to the complex pathogenic strategies, displaying a potential target for therapeutic intervention.

Prevalence of Extended-Spectrum β-Lactamases (ESBLs) Producing Aeromonas spp. Isolated from Lamellidens marginalis (Lamark, 1819) of Sewage-Fed Wetland: A Phenotypic and Genotypic Approach.

The global rise of zoonotic bacteria resistant to multiple antimicrobial classes and the growing occurrence of infections caused by Aeromonas spp. resistant to β-lactam antibiotics pose a severe threat to animal and human health. However, the contribution of natural environments, particularly aquatic ecosystems, as ideal settings for the development and spread of antimicrobial resistance (AMR) is a key concern. Investigating the phenotypic antibiotic resistance and detection of β-lactamase producing Aeromonas spp. in Lamellidens marginalis, which inhabit all freshwater ecosystems of the Indian subcontinent, is essential for implications in monitoring food safety and drug resistance. In the present investigation, 92 isolates of Aeromonas spp. were recovered from 105 bivalves and screened for their antimicrobial resistance patterns. In vitro antibiotic resistance profiling showed a higher Multiple Antibiotic Resistance (MAR) index of 0.8 with the highest resistance against ampicillin/sulbactam (82%), while 58, 44, 39 and 38% of the isolates were resistant to cephalothin, erythromycin, cefoxitin and imipenem, respectively. PCR results revealed that these isolates carried the blaTEM gene (94%), which was followed by the blaCTX-M gene (51%) and the blaSHV gene (45%). A combination of blaSHV, blaCTX-M, and blaTEM genes was found in 17% of the isolates, indicating the presence of all three resistance genes. This is the first investigation which highlights the importance of multidrug-resistant Aeromonas spp. in L. marginalis. The identification of extended-spectrum-β-lactamases (ESBLs) genes demand the necessity of continuous surveillance and systematic monitoring, considering its potential health risks for both animals and human beings.

Antimicrobial Resistance Profile and Extended Spectrum Beta-lactamase Resistance Genes in Escherichia coli from Patients in General Hospital, Karshi, Abuja, Nigeria

Aims: This study investigated the antimicrobial resistance profile and extended spectrum beta-lactamase resistance genes in Escherichia coli of from urine of patients sourced from General Hospital, Karshi, Abuja, Nigeria. Study Design: Cross-sectional study. Place and Duration of Study: Department of Microbiology, Nasarawa State University, Keffi, between August 2022 and February 2023. Methodology: A total of 120 samples were collected from patients. Escherichia coli was isolated from the samples using standard microbiological methods. Antibiotic susceptibility testing was evaluated as described by the Clinical and Laboratory Standards Institute (CLSI). The detection of ESBL production in E. coli isolates was carried out using double disc synergy test. In addition, molecular detection of ESBL genes was carried out using Polymerase Chain Reaction (PCR) method. Results: The prevalence of E. coli was 17.5% (21/120), out of which two (2) of the positive isolates (9.5%) were male, and 19 (90.5%) female. Antibiotic resistances in the isolates in decreasing order were as follows: sulphamethoxazole / trimethoprim (SXT: 81.0%), amoxicillin/clavulanic acid (AMC: 61.9%), ofloxacin (OFX: 66.7%), cefotaxime (CTX: 53.4%), gentamicin (CN: 42.9%), ceftriaxone (CRO: 33.3%), imipenem (IPM: 33.3%), meropenem (MOR: 42.4%), nitrofurantoin (NET: 20.3%) and ciprofloxacin (CIP: 23.8%). The commonest antibiotic resistant resistance phenotype was CIP-OFX-SXT (23.8%). Multiple antibiotic resistance (MAR) was observed in 90.5% (19/21) of the isolates, with the common MAR index being 0.3 (23.8%). Six of the twenty one beta-lactam resistant isolates (28.5%) were confirmed ESBL producers. The 6 ESBL positive isolates carried bla genes as follows: blaTEM (1/6, 16.7%) and blaCTX-M (1/6, 16.7%). blaSHV only was not found in any of the isolates. Conclusion: The E. coli isolates from urine of patients in General Hospital, Karshi, Abuja, Nigeria was less resistant to ciprofloxacin, nitrofurantoin, meropenem and imipenem. This implies that the antibiotics are useful in the treatment of infection caused by E. coli. Also, ESBL-positive E. coli isolates harbored ESBL genes, with blaCTX-M and blaTEM as the most common.

Molecular Characterization of Plasmid-mediated Quinolone Resistant Salmonella typhi From Patients Attending Federal Medical Center, Jabi, Abuja, Nigeria

Aims: This study investigates and reports the detection of qnr genes (plasmid-mediated quinolone resistance PMQR) in S.typhi isolated from stool of patients with suspected typhoid fever, in Federal Medical Center, Jabi, Abuja, Nigeria. Study Design: Cross sectional study. Place and Duration of Study: Department of Microbiology, Nasarawa State University, Keffi, between October 2022 and November 2023. Methodology: Salmonella typhi was isolated from stool of patients with suspected typhoid fever using standard culture and microbiological methods. Antibiotic susceptibility testing were performed using the disc diffusion method to investigate the ability of S. typhi to resist some antibiotics. Qnr genes (qnrC,qnrD,qnrS) were detected by PCR and amplification. Results: 17 out of 150 (11.3%) of the samples collected had S.typhi. Antibiotic resistance in the isolates in decreasing order were as follows: cefotaxime (100.0%), amoxicillin/ clavulanic acid (94.1%), nalidixic acid (94.1%), cefuroxime (94.1%), imipenems (88.2%), ceftriaxone/sulbactam (82.4%), ciprofloxacin (82.4%), gentamicin (58.8%), levofloxacin (47.1%) and ofloxacin (29.4%).The commonest antibiotic resistant phenotype was AUG- CTX-IMP-OFX-CN-NA-CXM-CRO-CIP-LBC at 29.4%. Multiple antibiotic resistance (MAR) was observed in 100% (17/17) of the isolates with the common MAR indices being 1.0 (29.4%), 0.7 (23.5%), 0.8 (17.6%) and 0.5 (17.6%). 33.3% of the isolates in FMCJ were positive for qnrC,qnrD,qnrS,qnrA+qnrC and qnrS+ aac(6′)-Ib-cr as all of qnrC qnrD,and qnrS genes were all expressed in the isolates. Conclusion: The S. typhi isolates showed lower resistances to ofloxacin, levofloxacin, and gentamicin, and all isolates were MAR, with resistance to 10 antibiotics being the most predominant. In addition, qnrC,qnrD, and qnrS resistance genes were all expressed in the isolates.

Antibiotic Resistance, Biofilm Formation, and Persistent Phenotype of Klebsiella pneumoniae in a Vietnamese Tertiary Hospital: A Focus on Amikacin.

Klebsiella pneumoniae stands out as a major opportunistic pathogen responsible for both hospital- and community-acquired bacterial infections. This study comprehensively assesses the antibiotic resistance, amikacin persistent patterns, and biofilm-forming ability of 247 isolates of K. pneumoniae obtained from an intensive care unit of a tertiary hospital in Vietnam. Microdilution assays, conducted on a 96-well plate, determined the minimum inhibitory concentrations (MICs) of amikacin. Susceptibility data for other antibiotics were gathered from the antibiogram profile. Stationary-phase bacteria were exposed to 50 × MIC, and viable bacteria counts were measured to determine amikacin persistence. Biofilm forming capacity on 96-well polystyrene surfaces was assessed by biomass and viable bacteria. The prevalence of resistance was notably high across most antibiotics, with 64.8% classified as carbapenem-resistant K. pneumoniae and 81.4% as multidrug resistant. Amikacin, however, exhibited a relatively low rate of resistance. Of the isolates, 58.2% demonstrated a moderate to strong biofilm formation capacity, and these were found to be poorly responsive to amikacin. K. pneumoniae reveals a significant inclination for amikacin persistence, with ∼45% of isolates displaying an antibiotic antibiotic-survival ratio exceeding 10%. The study sheds light on challenges in treating of K. pneumoniae infection in Vietnam, encompassing a high prevalence of antibiotic resistance, a substantial ability to form biofilm, and a notable rate of antibiotic persistence.

Biofilm-producing and carbapenems-resistant Escherichia coli nosocomial uropathogens: a cross-sectional study.

This cross-sectional study aims to determine the incidence and potential risk factors associated with biofilm-producing uropathogenic Escherichia coli (UPEC) nosocomial strains from a tertiary care hospital and to examine the prospective correlation between biofilm generation and antibiotic resistance phenotypes and genotypes. A total of 130 UPEC nosocomial isolates were identified, their biofilm formation was quantified using a modified microtiter plate assay, and their antibiotic susceptibilities were assessed utilizing the disc diffusion method. Isolates were then subjected to PCR assays targeting blaKPC, blaVIM, blaIMP, and blaOXA48 genes. Over half of the isolates (n = 76, 58.5%) were biofilm producers. Among 17 carbapenem-resistant isolates, 6 (42.9%) isolates harbored the blaOXA48 gene, and only 1 (9.1%) isolate was positive for the blaVIM gene. Prior antibiotic therapy (aOR 15.782, p 0.000) and diabetes mellitus DM (aOR 11.222, p 0.016) were the significant risk factors associated with biofilm production, as determined by logistic regression analysis of the data. In addition, gentamicin resistance was the only statistically significant antibiotic resistance pattern associated with biofilm production (aOR 9.113, p 0.02). The findings of this study emphasize the significance of implementing proper infection control measures to avoid the horizontal spread of biofilm formation and associated antimicrobial resistance patterns among UPEC nosocomial strains.

Coexistence of blaIMP−4 and blaSFO−1 in an IncHI5B plasmid harbored by tigecycline-non-susceptible Klebsiella variicola strain

BackgroundKlebsiella variicola is considered a newly emerging human pathogen. Clinical isolates of carbapenemase and broad-spectrum β-lactamase-producing K. variicola remain relatively uncommon. A strain of K. variicola 4253 was isolated from a clinical sample, and was identified to carry the blaIMP−4 and blaSFO−1 genes. This study aims to discern its antibiotic resistance phenotype and genomic characteristics.MethodsSpecies identification was conducted using MALDI-TOF/MS. PCR identification confirmed the presence of the blaIMP−4 and blaSFO−1 genes. Antibiotic resistance phenotype and genomic characteristics were detected by antimicrobial susceptibility testing and whole-genome sequencing. Plasmid characterization was carried out through S1-PFGE, conjugation experiments, Southern blot, and comparative genomic analysis.ResultsK. variicola 4253 belonged to ST347, and demonstrated resistance to broad-spectrum β-lactamase drugs and tigecycline while being insensitive to imipenem and meropenem. The blaIMP−4 and blaSFO−1 genes harbored on the plasmid p4253-imp. The replicon type of p4253-imp was identified as IncHI5B, representing a multidrug-resistant plasmid capable of horizontal transfer and mediating the dissemination of drug resistance. The blaIMP−4 gene was located on the In809-like integrative element (Intl1-blaIMP−4-aacA4-catB3), which circulates in Acinetobacter and Enterobacteriaceae.ConclusionsThis study reports the presence of a strain of K. variicola, which is insensitive to tigecycline, carrying a plasmid harboring blaIMP−4 and blaSFO−1. It is highly likely that the strain acquired this plasmid through horizontal transfer. The blaIMP−4 array (Intl1-blaIMP−4-aacA4-catB3) is also mobile in Acinetobacter and Enterobacteriaceae. So it is essential to enhance clinical awareness and conduct epidemiological surveillance on multidrug-resistant K. variicola, conjugative plasmids carrying blaIMP−4, and the In809 integrative element.

Prevalence and transmission of extensively drug-resistant Salmonella enterica serovar Kentucky ST198 based on whole-genome sequence in an intensive laying hen farm in Jiangsu, China

Salmonella, which is widely distributed in nature, is an important zoonotic pathogen affecting humans, livestock, and other animals. Salmonella infection not only hinders the development of livestock and poultry-related industries but also poses a great threat to human health. In this study, we collected 1,537 samples including weak chicks, dead embryos, fecal samples and environmental samples from 2020 to 2023 (for a period of 1 to 2 months per year) to keep a long-term monitor the prevalence of Salmonella in an intensive laying hen farm, 105 Salmonella strains were isolated with an isolation rate of 6.83% (105/1,537). It revealed a significant decrease in prevalence rates of Salmonella over time (P < 0.001). Before 2020, the predominant serotype was S. Enteritidis. S. Kentucky was first detected in November 2020 and its proportion was gradually found to exceed that of S. Enteritidis since then. S. Kentucky isolates were distributed in various links of the four regions in the poultry farm. A total of 55 S. Kentucky strains, were assigned to ST198 based on whole genome sequencing. Among them, 54 strains were resistant to 12 to 16 antibiotics, indicating that they were extensively drug-resistant (XDR). Seventeen antimicrobial resistance genes were detected in 55 S. Kentucky isolates. For most of these isolates, antibiotic resistance phenotypes were concordant with their genotypes. All S. Kentucky strains isolated from this farm in 2020 to 2023 showed a high similarity based on their core-genome SNP-based phylogeny. The traceability analysis revealed that S. Kentucky was introduced to the farm through newly purchased flocks. The long-term existence of XDR S. Kentucky ST198 poses a substantial risk because of the multiage management and circulation of workers in this poultry farm. Thus, this study is the first to report extensively drug-resistant S. Kentucky ST198 detected in this intensive poultry farm in China.

Prevalence and antimicrobial susceptibility of Pasteurella multocida isolated from goats in Can Tho city

A total of 289 goats’ nasal swabs were collected from March to May 2023 to determine the prevalence of Pasteurella multocida in goats raised on medium-scale farms in Can Tho city. There were 143 samples representing 49.48% positive for Pasteurella multocida. Of 143 positive samples, 64 strains were selected to examine the antimicrobial susceptibility using the disk diffusion method. The results showed that those strains were still sensitive to 6/7 examined antibiotics, especially doxycycline (100%); however, they were highly resistant to ampicillin (53.13%). There were 9 phenotypes of antibiotic resistance (60.94%), with the most common patterns of ampicillin and ampicillin + amoxicillin/clavulanic acid (23.44%).By using PCR assay to detect antibiotic resistance genes, the results revealed that sulII gene was the most frequent detection (67.19%). A total of 11 resistance genotypes detected in 54 strains accounted for 84.38%, and the pattern of aadB + sulII was the most common genotype accounting for 23.44%. Therefore, the prevalence and antimicrobial susceptibility of P. multocida in goats should be controlled to protect their health and prevent spreading in husbandry environments.