Kirby-Bauer Disk Diffusion Test Research Articles

Genetic Diversity and Zoonotic Potential of Shiga Toxin-Producing E. coli (STEC) in Cattle and Buffaloes from Islamabad, Pakistan

Shiga toxin-producing E. coli (STEC) are considered important zoonotic pathogens of great economic significance, associated with diarrhea, hemolytic uremic syndrome (HUS), hemorrhagic colitis (HC), and death in humans. This study aimed to investigate the distribution of various STEC virulence gene markers and antimicrobial susceptibility (AST) profiles associated within E. coli isolates from the recto-anal mucosal swabs (RAMSs) of slaughtered cattle and buffaloes in Islamabad, Pakistan. The RAMSs (n = 200) were analyzed using multiplex PCR for the presence of stx1, stx2, eae, and ehxA genes. Samples that were positive for one or more of the virulence genes were inoculated with Sorbitol MacConkey agar (SMAC) for isolation of STEC. The isolates were further analyzed for the presence of virulence genes using multiplex PCR. Of the 200 RAMS, 118 (59%) were positive for one or more virulence genes. E. coli isolates (n = 18) with one or more virulence genes were recovered from the 118 positive samples. The DNA of the isolates positive for one or more virulent genes was extracted and subjected to whole genome sequencing using Illumina. Analysis of the WGS data indicated that the E. coli isolates could be differentiated into 11 serotypes. Most E. coli isolates (13/18; 72.2%) carried five genes (stx1, stx2, Iha, iss, and IpfA) in various combinations. In addition to these five genes, other virulence genes identified in these isolates were espI, ireA, espP, exhA, epeA, mcmA, mch, ast, celB, eilA, katP, and capU. The AST was performed using the Kirby–Bauer disk diffusion test. The study indicated that all the isolates were resistant to rifampicin and a significant proportion of the isolates were MDR. A wide range of antimicrobial resistance genes (ARGs) were detected among the isolates, reflecting the complex nature of resistance mechanisms. The study results indicate that cattle and buffaloes slaughtered in Islamabad might be the carriers of antimicrobial resistant STEC of zoonotic significance, thus representing a source of human infection.

PHYSICOCHEMICAL AND BACTERIOLOGICAL ANALYSIS OF BOREHOLE WATER FROM EIGHT SELECTED LOCATIONS WITHIN BENIN METROPOLIS, EDO STATE, NIGERIA

In Nigeria, borehole water is a dominant source of drinking water. The quality of the water has diminished substantially due to various anthropogenic activities. Thus, this study seeks to x-ray the physicochemical and bacteriological quality of borehole water in some crowded localities in Benin City, Edo State, Nigeria. Heterotrophic plate count and total coliform count were carried out sing pour plate method. Antibiotic susceptibility test was done using the Kirby-Bauerdisc diffusion test. Except for one case each of iron (0.32 ± 0.11), Manganese (0.16 ± 0.06), Cadmium (0.005 ± 0.01) and Lead (0.12 ± 0.01) that were found to be above the recommended WHO and NAFDAC limits, the heavy metals had concentration levels that were within the stipulated limits. Isolates were phenotypically and molecularly identified as:Klebsiella aerogenes, strain OBANOR&OKWU 100; Streptococcus pneumoniae, OBANOR&OKWU 101; Pseudomonas aeruginosa, OBANOR&OKWU 102; Staphylococcus aureus, OBANOR&OKWU 103 and Micrococcus lylae, OBANOR&OKWU 104 using the 16S rRNA gene analysis. Isolates were deposited in the United States GenBank under accession numbers: OK017170, OK017423, OK017480, OK017486 and OK019091 respectively. Generally, the isolates showed low resistance rates (14.29 % - 19.05 %) to the antibiotics used in this study except for Cefuroxime and Ampicillin with extremely high resistance rates of 80.95 % and 85.71 % respectively. Majority of borehole water samples were found to be contaminated. This study highlights the need for continuous monitoring and quality assessment of the borehole water available for consumption.

Coagulase-negative staphylococci from bovine milk: Antibiogram profiles and virulent gene detection

BackgroundCoagulase-negative Staphylococcus species are an emerging cause of intramammary infection, posing a significant economic and public health threat. The aim of this study was to assess the occurrence of coagulase-negative Staphylococcus species in bovine milk and dairy farms in Northwestern Ethiopia and to provide information about their antibiotic susceptibility and virulence gene profiles.MethodsThe cross-sectional study was conducted from February to August 2022. Coagulase-negative Staphylococcus species were isolated from 290 milk samples. Species isolation and identification were performed by plate culturing and biochemical tests and the antimicrobial susceptibility pattern of each isolate was determined by the Kirby-Bauer disc diffusion test. The single-plex PCR was used to detect the presence of virulent genes. The STATA software version 16 was used for data analysis. The prevalence, proportion of antimicrobial resistance and the number of virulent genes detected from coagulase-negative Staphylococcus species were analyzed using descriptive statistics.ResultsCoagulase-negative Staphylococcus species were isolated in 28.6%, (95% CI: 23.5–34.2) of the samples. Of these, the S. epidermidis, S. sciuri, S. warneri, S. haemolyticus, S. simulans, S. chromogens, S. cohnii, and S. captis species were isolated at the rates of 11, 5.2, 3.4, 3.1, 3.1, 1, 1, and 0.7% respectively. All the isolates showed a high percentage (100%) of resistance to Amoxicillin, Ampicillin, and Cefotetan and 37.5% of resistance to Oxacillin. The majority (54.2%) of coagulase-negative isolates also showed multidrug resistance. Coagulase-negative Staphylococcus species carried the icaD, pvl, mecA, hlb, sec, and hla virulent genes at the rates of 26.5%, 22.1%, 21.7%, 9.6%, 9.6% and 8.4% respectively.ConclusionThe present study revealed that the majority of the isolates (54.2%) were found multidrug-resistant and carriage of one or more virulent and enterotoxin genes responsible for intramammary and food poisoning infections. Thus, urgent disease control and prevention measures are warranted to reduce the deleterious impact of coagulase-negative species. To the best of our knowledge, this is the first study in Ethiopia to detect coagulase-negative Staphylococcus species with their associated virulent and food poisoning genes from bovine milk.

Właściwości i zastosowanie gruzińskiego naturalnego filipsytu

Oceanic and terrestrial sedimentary phillipsites make up very large reserves, but the use of this natural zeolite is not so wide comparing to clinoptilolite, and purpose of our study was to characterize the phillipsites of the Georgian deposits and highlight their possible application. It is shown that natural phillipsite can be used as a raw material for the synthesis of phase-pure zeolite NaX with Si/Al~1.5-1.7 in the form of octahedral crystallites with uniform micrometric (2-7 μm) dimensions, characterized by high specific surface area (590-770 m2/g) and volume of pores (0.58 cm3/g) including uniform zeolitic micropores and channels with an average diameter of 55 nm, which opens up the prospect of its use in catalysis. It has been established that natural phillipsite is a suitable carrier of bioactive metals: silver-, copper-, and zinc-containing micro-mesoporous materials have been prepared using ion-exchange reactions between zeolite and a salt of a transition metal; the products contain up to 235 mg/g of silver, 85 mg/g of copper, and 87 mg/g of zinc, and in the Kirby-Bauer disk-diffusion test show strong bacteriostatic activity against such microorganisms as gram-negative bacterium Escherichia coli, gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, fungal pathogenic yeast Candida albicans and a fungus Aspergilus niger. The use of bactericidal materials obtained on the basis of natural phillipsite is possible both for water purification and disinfection, and as fillers in the production of polymeric materials, paper and cardboard.

Gram Positive Cocci Associated Urinary Tract Infections, their Prevalence and Antibiotic Susceptibility Patterns

Background: Urinary tract infections (UTIs) are the third most common type of infection in humans globally. Gram-positive bacteria are said to be responsible for ten percent of urinary tract (UTI) infections. The study's goal was to profile gram-positive cocci-associated UTIs and their antibiogram, as they were observed at LASUTH. Methods: This was a retrospective assessment of the Medical Microbiology Laboratory records of the LASUTH to review the in vitro antibiotic susceptibility patterns of gram-positive urinary bacterial isolates between April 2020 and March 2021. The bacteria were isolated and identified from routine urine samples using standard bacteriological methods and the API. In vitro antibiotic susceptibility test (AST) was routinely performed by the modified Kirby-Bauer disk diffusion test and susceptibility breakpoints were determined using the Clinical and Laboratory Standards Institute (CLSI) guidelines. Results: 2,253 urine samples were processed in the medical microbiology laboratory over the one year and 662 (29.4%) samples yielded Positive cultures. Of the 662 isolates, 494 (74.6%) were gram-negative bacteria. 164 (24.8%) were gram-positive cocci while 4 (0.6%) were gram positive rod. Among the gram-positive cocci’s isolated Enterococcus faecalis had the highest frequency 58 (35.4%). Aminoglycosides (Gentamycin and Amikacin) and Linezolid antibiotics were found to be the most effective drugs against gram-positive cocci bacteria except Enterococcus spp. For empirical treatment of Enterococcus spp in our facility Fosfomycin and Tigecycline are the best options, while for Streptococcus agalactiae associated UTI, Amikacin, Cefuroxime, Linezolid, and levofloxacin can be used for empirical treatment. Conclusion: The prevalence rate of gram-positive cocci associated UTI in this study was 7.3% (164/2253). The emergence of drug resistance in these pathogens to commonly used antibiotics is a thing of concern. Therefore, efficient antimicrobial stewardship programmes must be in place.

Chemical fingerprinting, antimicrobial, antioxidant, anti-inflammatory, and anticancer potential of greenly synthesized silver nanoparticles from pistachio (Pistacia vera) nuts and senna (Cassia angustifolia Vahl.) leaves.

There is a growing interest in standardizing the biocompatible, cost-effective, and eco-friendly manufacturing techniques for metallic nanostructures due to their widespread applications in the industrial and medical sectors. In recent decades, green synthesis has been proven as the most suitable technique for synthesizing metal nanoparticles. The present research study investigates the use of Cassia angustifolia (senna) leaves and Pistacia vera (Pistachio) nuts to prepare crude aqueous extracts, ethanolic extracts, and biogenic silver nanoparticles (AgNPs). The prepared aqueous extracts were used as reducing, stabilizing, and capping agents for the production of silver nanoparticles. These AgNPs were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and ultraviolet-visible (UV-Vis) spectroscopy. The outcomes validated the formation of stable AgNPs with bioactive functional components. Invitro antibacterial, anticancer, anti-inflammatory, and antioxidant potentials were assessed by Kirby-Bauer disk diffusion test, MIC test, MBC test, MTT assay, BSA denaturation inhibition assay, and DPPH antioxidant assay, respectively. Results confirmed that the tested plant extract possesses a variety of bioactive compounds with various biological activities and is therapeutically effective. These findings verified that C. angustifolia and P. vera are promising bioresources for the synthesis of therapeutic extracts and nanostructures with commendable therapeutic potency.

Characterization of resistance genes and replicon typing in Carbapenem-resistant Klebsiella pneumoniae strains

ObjectiveIn our study, K. pneumoniae strains (non-susceptible to carbapenem) (n = 60) were obtained from various clinical samples from Rize State Hospital between 2015 and 2017 and it is aimed to identify antibiotic resistance genes and replicon typing.MethodsAntibiotic susceptibility tests of the strains were performed with Kirby-Bauer disk diffusion test and the Vitek-2 automated system (BioMerieux, France). Antibiotic resistance genes and replicon typing was characterized by PCR method.ResultsIt was determined that K. pneumaniae isolates were mostly isolated from the samples of the intensive care unit. All of the K. pneumoniae strains examined in this study were found to be ampicillin/sulbactam and ertapenem resistant but colistin susceptible. Amoxacillin/clavulonic acid resistance was detected at 98.14% of strains. The blaOXA-48 gene was mostly detected in isolates. The most common type of plasmid was I1 and 3 different plasmid types were found in five different strains together.ConclusionThis study also shows that the distribution of NDM-1 and OXA-48 carbapenemases has increased since the first co-display in Türkiye and that IncHI1 is the first record in our country. This study provides an overview of the major plasmid families occurring in multiple antibiotic-resistant strains of K. pneumoniae. To our knowledge, this study represents the first report of IncHI1 record in Türkiye.

Experiment to Demonstrate Pesticide-Induced Antimicrobial Resistance (AMR): An Emerging Health Threat.

Background Pesticides, including insecticides, herbicides, and fungicides, are essential for global food production, boosting crop yields, and preventing disease transmission. However, their excessive and improper use raises concerns about potential long-term consequences, affecting microbial ecosystems and fostering antimicrobial resistance. Materials and methods The objective of the study was to identify the effect of the pesticide compound (Imidacloprid17.1% w/w) on the ATCCEscherichia coli. An experiment was conducted on ATCCEscherichia coli27852. A 0.5 McFarland suspension of the strain was incubated in the presence of a pesticide compound (Imidacloprid17.1% w/w) at a dilution of 1:4, 1:8, and 1:16. at 370C. Antibiotic susceptibility for cefoxitin, ciprofloxacin, ceftazidime, amikacin, and imipenem was determined via the Kirby-Bauer disk diffusion test at intervals of 24 hours, 48 hours, seven days, and 21 days. The results were then compared to the standard zone of inhibition diameter for ATCCEscherichia coli27852 by Clinical and Laboratory Standards Institute (CLSI) guidelines. Results No bacterial growth was detected at pesticide dilutions of 1:1 and 1:2, indicating their inability to tolerate high pesticide concentrations. However, growth became evident at a 1:4 dilution and beyond, with mutants thriving within the inhibition zone. The experiment caused significant alterations in the inhibition zone sizes for all antibiotics, especially notable with imipenem, amikacin, and ceftazidime compared to the initial zone size for ATCCEscherichia coli27852. Conclusion Our study concludes that the pesticide (Imidacloprid 17.1% w/w) significantly influences antibiotic resistance, especially with carbapenems, aminoglycosides, and cephalosporins in the tested groups at various concentrations and durations of exposure.

Molecular typing of clinical and non-clinical <i>Escherichia coli</i> from Rivers State, Nigeria using amplification-based RAPD and ERIC-PCR typing methods

Due to the diverse nature of Escherichia coli, typing of these organisms is essential. This can provide key epidemiological information not just on the strains in circulation and their relationship, but also on the development and spread of drug resistant clones. Affordable PCR-based typing techniques have resulted in an increase in typing studies particularly in resource limited settings. But information from Nigeria on strain typing is limited. This study was therefore aimed at typing clinical and non-clinical strains of E. coli from Nigeria using the PCR based Random Amplification of Polymorphic DNA (RAPD) and Enterobacterial Repetitive Intergenic Consensus-PCR (ERIC-PCR) typing methods. 
 E. coli was isolated from clinical and non-clinical sources using Eosin Methylene Blue agar. Characteristic green metallic sheen colonies associated with E. coli were purified, identities determined using standard biochemical tests and confirmed using molecular methods. Susceptibility testing was carried out using the modified Kirby-Bauer disc diffusion test and RAPD and ERIC-PCR typing carried out on 48 confirmed E. coli isolates as previously described. ERIC-PCR typing resulted in the generation of 38 unique patterns with a 0.94 diversity. Nine of these were singletons comprised of only a single isolate, while the remaining 29 patterns were grouped to 10 clusters. RAPD gave similar results of 37 patterns, 9 singletons, 0.94 diversity and 13 clusters. For ERIC-PCR, all isolates with identical patterns were from the same source. RAPD, however, had identical patterns present in isolates from different sources. 
 Using the ERIC-PCR typing method, this study was able to identify non-clinical isolates as distinct from the clinical E. coli isolates as evidenced by 100% identical ERIC-PCR profiles of isolates from the same source and a lack of 100% relatedness in isolates from different sources.

Genomic Characterization and Safety Assessment of Bifidobacterium breve BS2-PB3 as Functional Food.

Our group had isolated Bifidobacterium breve strain BS2-PB3 from human breast milk. In this study, we sequenced the whole genome of B. breve BS2-PB3, and with a focus on its safety profile, various probiotic characteristics (presence of antibiotic resistance genes, virulence factors, and mobile elements) were then determined through bioinformatic analyses. The antibiotic resistance profile of B. breve BS2-PB3 was also evaluated. The whole genome of B. breve BS2-PB3 consisted of 2,268,931 base pairs with a G-C content of 58.89% and 2,108 coding regions. The average nucleotide identity and whole-genome phylogenetic analyses supported the classification of B. breve BS2-PB3. According to our in silico assessment, B. breve BS2-PB3 possesses antioxidant and immunomodulation properties in addition to various genes related to the probiotic properties of heat, cold, and acid stress, bile tolerance, and adhesion. Antibiotic susceptibility was evaluated using the Kirby-Bauer disk-diffusion test, in which the minimum inhibitory concentrations for selected antibiotics were subsequently tested using the Epsilometer test. B. breve BS2-PB3 only exhibited selected resistance phenotypes, i.e., to mupirocin (minimum inhibitory concentration/MIC >1,024 μg/ml), sulfamethoxazole (MIC >1,024 μg/ml), and oxacillin (MIC >3 μg/ml). The resistance genes against those antibiotics, i.e., ileS, mupB, sul4, mecC and ramA, were detected within its genome as well. While no virulence factor was detected, four insertion sequences were identified within the genome but were located away from the identified antibiotic resistance genes. In conclusion, B. breve BS2-PB3 demonstrated a sufficient safety profile, making it a promising candidate for further development as a potential functional food.

Occurrence of Imipenem-Resistant Uropathogenic Escherichia coli in Pregnant Women: An Insight into Their Virulence Profile and Clonal Structure.

Uropathogenic Escherichia coli (UPEC) is the predominant pathogen in Urinary Tract Infection (UTI) in pregnant and non-pregnant women. Limited studies were initiated to explore UPEC from pregnant women with respect to imipenem resistance, pathogenicity, and their clonal lineage. In this study, imipenem resistance, phylogenetic background, virulence-associated genes, and clonal characteristics in UPECs isolated from pregnant and non-pregnant cohorts were investigated. E. coli was identified biochemically from urine culture-positive samples from pregnant and non-pregnant women. Carbapenem (meropenem, ertapenem, imipenem) susceptibility was determined by Kirby-Bauer disk diffusion test. The pathogenic determinants were identified by PCR. MEGA 11 was used to interpret clonal lineages from MLST. GraphPad Prism 8.0 and SPSS 26.0 were used for statistical interpretation. Results indicated highest resistance against imipenem compared to meropenem and ertapenem in UPECs isolated from pregnant (UPECp; 63.89%) and non-pregnant (UPECnp; 87.88%) women. Although phylogroup E was predominant in both imipenem-resistant isolates, acquisition of virulence factors was higher among UPECnp than UPECp. Akin to this observation, the presence of PAI III536 and PAI IV536 was statistically significant (p < 0.05) in the former. MLST analysis revealed similar clonal lineages between UPECnp and UPECp, which showed an overall occurrence of ST405 followed by ST101, ST410, ST131, and ST1195 in UPECnp and ST167 in UPECp, respectively, with frequent occurrence of CC131, CC405. Therefore, imipenem-resistant UPECp although discrete with respect to their virulence determinants when compared to UPECnp shared similar STs and CCs, which implied common evolutionary history. Thus, empiric treatment must be restricted in UTIs to especially protect maternal and fetal health.

Prevalence and Antimicrobial Characteristics of Escherichia coli in Selected Vegetables and Herbs in Bangkok, Thailand

Raw vegetables and herbs are exposure sources of foodborne pathogens. This study examined the prevalence and antimicrobial resistance of Escherichia coli in five types of fresh vegetables and herbs: spearmint (Mentha spicata), leaf lettuce (Lactuca sativa var. crispa), coriander (Coriandrum sativum), Chinese cabbage (Brassica rapa subsp. pekinensis), and cucumber (Cucumis sativus). Produce samples (n = 300) were acquired from local open markets and supermarkets in Bangkok, Thailand. Each produce sample was preenriched in buffered peptone water and then enriched in E. coli broth. A loopful of the second enrichment was transferred onto selective media for subsequent confirmation and biochemical tests. The Kirby-Bauer disk diffusion test was employed to assess E. coli susceptibility to selected antibiotics (twelve antibiotics of seven classes). The latex agglutination test was performed to serotype the isolates for O157 and H7 antigens. A commercial test kit was used to determine the presence of Shiga toxin-producing E. coli (STEC). For all samples, the prevalence of E. coli was found to be 32.0% (96/300), whereby produce from supermarkets had a higher prevalence than those from local markets at 40.7% (61/150) and 23.3% (35/150), respectively. Among different types of produce, leaf lettuce had the highest E. coli prevalence at 36.7% (22/60), followed by cucumber and spearmint, coriander, and Chinese cabbage, at 35.0% (21/60), 35.0% (21/60), 35.0% (21/60), and 18.3% (11/60), respectively. Of the positive isolates, 27.1% (26/96) showed multidrug resistance. All isolates (100%) showed resistance to penicillin but varying resistant characteristics for tetracycline, ampicillin, and amoxicillin, with resistance rates of 31.3% (30/96), 31.3% (30/96), and 31.3% (30/96), respectively. Two of the 96 isolates (1.1%) were positive for the O157 antigen but negative for the H7 antigen. No STEC was observed. This study established baseline information regarding the prevalence of E. coli and its antimicrobial resistance profile in produce in Bangkok, Thailand.

Detection of extended-spectrum beta-lactamases and carbapenemases in clinical isolates of Stenotrophomonas maltophilia in the northeast of Iran

PurposeStenotrophomonas maltophilia has emerged as an important pathogen associated with significant mortality in pneumonia and bacteremia of severely immunocompromised, hospitalized patients. The main objectives of the present study are to describe the surveillance of antibiotic resistance and to detect the genes encoding extended-spectrum beta-lactamases (ESBLs) and carbapenemase enzymes in clinical S. maltophilia isolates from blood cultures in the northeast of Iran. MethodsA total of 114 clinical human isolates of S. maltophilia were collected from blood cultures of patients admitted at three teaching hospitals in Mashhad, northeast of Iran. Antimicrobial susceptibility was determined by the Kirby-Bauer disk diffusion test. The extended-spectrum beta-lactamase (ESBL) production was confirmed by the combination disk method. The PCR was applied for molecular epidemiology of ESBLs and carbapenemase coding genes. ResultsOverall, 10 % and 8 % of isolates were resistant to co-trimoxazole and levofloxacin, respectively. The prevalence of the blaTEM, blaSHV, and blaCTX-M-15 genes in the 69 ESBL-producing isolates was 2.9 %, 5.8 %, and 10.14 %, respectively. Moreover, the prevalence of the blaKPC-1, blaIMP, blaVIM, blaNDM, and blaOXA-48 genes was 18.42 % (n = 21), 4.39 % (n = 5), 6.14 % (n = 7), 15.79 % (n = 18), and 14.91 % (n = 17), respectively. ConclusionFor the first time in Iran, ESBLs and carbapenemase coding genes have been identified in human clinical strains of S. maltophilia. Circulation of these resistant strains with transferable genes is a sign of flow of resistome genes from other bacterial genera to S. maltophilia, most probably leading to the evolution of the superbugs of this bacterium.

Cupferron impairs the growth and virulence of Escherichia coli clinical isolates.

Multidrug resistance is a worrying problem worldwide. The lack of readily available drugs to counter nosocomial infections requires the need for new interventional strategies. Drug repurposing represents a valid alternative to using commercial molecules as antimicrobial agents in a short time and with low costs. Contextually, the present study focused on the antibacterial potential of the ammonium salt N-nitroso-N-phenylhydroxylamine (Cupferron), evaluating the ability to inhibit microbial growth and influence the main virulence factors. Cupferron cytotoxicity was checked via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and hemolysis assays. The antimicrobial activity was assessed through the Kirby-Bauer disk diffusion test, broth microdilution method and time-killing kinetics. Furthermore, the impact on different stages of the biofilm life cycle, catalase, swimming and swarming motility was estimated via MTT and crystal violet (CV) assay, H2O2 sensitivity and motility tests, respectively. Cupferron exhibited less than 15% cytotoxicity at 200 μg/mL concentration. The 90% bacterial growth inhibitory concentrations (MIC90) values recorded after 24 hours of exposure were 200 and 100 μg/mL for multidrug-resistant (MDR) and sensitive strains, respectively, exerting a bacteriostatic action. Cupferron-treated bacteria showed increased susceptibility to biofilm production, oxidative stress and impaired bacterial motility in a dose-dependent manner. In the new antimicrobial compounds active research scenario, the results indicated that Cupferron could be an interesting candidate for tackling E. coli infections.

Designing a Multiplex PCR for Rapid and Accurate Detection of Metallobetalactamases Resistant Genes from Acinetobacter baumaniiIsolates in Tehran City, Iran.

Acinetobacter baumannii strains harboring Meallobetalactamases (MBL) pose a significant threat in the context of nosocomial infections. The present investigation was undertaken with the objective of devising a Multiplex PCR methodology for the concurrent detection of MBL genes within A. baumannii strains prevalent in Tehran City, Iran. Between October 2020 and February 2021, 100 strains of A. baumannii were procured from burn specimens of hospitalized patients at Motahhari Hospital in Tehran. The identification of A. baumannii strains involved conventional biochemical techniques, coupled with confirmation of the presence of the bla OXA-51 gene. Antibiotic susceptibility was assessed using the Kirby-Bauer disc diffusion test. MBL-producing strains were characterized through a phenotypic approach employing the combined disk test, alongside Multiplex PCR for the simultaneous identification of bla VIM, bla IMP, bla GIM, and bla NDM genes. Statistical analyses were conducted using the chi-square test, with SPSS version 20.0 employed for data processing. Among 100 strains examined, 96.1% exhibited positivity for MBL, as determined by the combined disk test. The study revealed a predominance of extensively drug-resistant (XDR) strains, with colistin demonstrating the highest level of sensitivity. The genotypic assay unveiled that Multiplex PCR identified bla VIM, bla NDM, and bla IMP in 20 strains, bla VIM and bla NDM in 30 strains, and exclusively the bla NDM gene in 45 strains. Notably, the Multiplex PCR technique exhibited the capacity to concurrently detect MBL genes (bla VIM, bla IMP, bla GIM, bla NDM) in 2 strains. The current investigation underscores prevalence of the bla NDM gene within clinical strains of A. baumannii. Furthermore, Multiplex PCR emerges as a robust and highly sensitive technique for rapid discernment of the MBL genes within in A. baumannii strains.

Phenotype and genotype analysis for Helicobacter pylori antibiotic resistance in outpatients: a retrospective study.

To investigate the antibiotic resistance of Helicobacter pylori (H. pylori) in outpatients and to explore the consistency between genotype and phenotype of H. pylori antibiotic resistance. A retrospective study on outpatients screened with urea breath test for H. pylori infection in Nanjing First Hospital from April 2018 to January 2022. Patients who tested positive underwent a consented upper endoscopy, and the H. pylori infection was confirmed by rapid urease test (RUT) and H. pylori culture. For antibiotic resistance phenotype analysis, the H. pylori strains isolated from gastric biopsy were tested for antibiotic resistance phenotype by the Kirby-Bauer disk diffusion test. In addition, the antibiotic resistance genotype of isolated H. pylori was tested with a real-time polymerase chain reaction. A total of 4,399 patients underwent H. pylori infection screening, and 3,306 H. pylori strains were isolated. The antibiotic resistance phenotype test revealed that the resistance rates of metronidazole (MTZ), clarithromycin (CLR), levofloxacin (LEV), amoxicillin (AMX), furazolidone (FR), and tetracycline (TE) were 74.58%, 48.61%, 34.83%, 0.76%, 0.27%, and 0.09%, respectively. Additionally, the antibiotic resistance genotype test revealed that rdxA gene mutation A610G (92.96%), A91G (92.95%), C92A (93.00%), and G392A (95.07%) were predominant in H. pylori with MTZ resistance; 23S rRNA gene mutation A2143G (86.47%) occurred in most H. pylori with CLR resistance; and gyrA gene mutation 87Ile/Lys/Tyr/Arg (97.32%) and 91Asn/Gly/Tyr (90.61%) were the most popular mutations in strains with LEV resistance. The phenotypic resistance and genotypic resistance to CLR (kappa value = 0.824) and LEV (kappa value = 0.895) were in good agreement. The history of eradication with MTZ, CLR, LEV, and AMX was correlated with H. pylori resistance. In short, this study demonstrated that drug resistance of H. pylori was mainly to MTZ, CLR, and LEV in local outpatients. Three drugs can be selected for increased MICs (Minimum Inhibitory Concentration) via single chromosomal mutations. In addition, the genotype could be used to predict the phenotypic H. pylori resistance to CLR and LEV. IMPORTANCE Helicobacter pylori is a key bacterium that causes stomach diseases. There was a high prevalence of H. pylori in the Chinese population. We analyzed the resistance phenotype and genotype characteristics of H. pylori in 4,399 outpatients at the First Hospital of Nanjing, China. We found a higher resistance rate to metronidazole (MTZ) , clarithromycin (CLR), and levofloxacin (LEV), and the genotype could be used to predict the phenotypic H. pylori resistance to CLR and LEV. This study provides information on H. pylori infection and also provides guidance for clinical doctors' drug treatment.

Antibiotic susceptibility profiles of Gram-negative bacterial uropathogens in a tertiary hospital, southwest Nigeria

Background: Increasing rates of antibiotic resistance have made it necessary to regularly monitor antibiotic susceptibility patterns of gram negative bacterial uropathogens in order to optimize antibiotic therapy for urinary tract infections. The aim of this study was to analyze the antibiotic susceptibility patterns of Gram-negative bacterial uropathogens in Babcock University Teaching Hospital, Ilishan-Remo, southwest Nigeria.&#x0D; Methodology: This study was a retrospective review of the Medical Microbiology Laboratory records of the hospital to analyze the in vitro antibiotic susceptibility patterns of Gram-negative urinary bacterial isolates between May 2016 and April 2022. The bacteria were isolated and identified from routine urine samples using standard bacteriological methods. In vitro antibiotic susceptibility test (AST) to amoxicillin-clavulanate, piperacillin-tazobactam, ceftriaxone, ceftazidime, nitrofurantoin, ciprofloxacin and meropenem was routinely performed by the modified Kirby-Bauer disk diffusion test and susceptibility break points determined using the Clinical and Laboratory Standards Institute (CLSI) guidelines.&#x0D; Results: A total number of 3,549 urine samples were processed during the period of review, and 808 (22.8%) samples yielded positive bacterial cultures. Of the 808 isolates, 604 (74.8%) were Gram-negative bacteria. The most frequently isolated Gram-negative bacteria were Escherichia coli (41.9 %) and Klebsiella spp (27.5%) while Pseudomonas spp and Proteus spp accounted for 4.3% and 1.0% of all isolates respectively. Meropenem had the highest in vitro antibacterial activity (74.3% to 90.3% of isolates were sensitive) for all isolates. Overall, E. coli, Klebsiella spp., and Proteus spp. showed high resistance rates to amoxicillin-clavulanate (65.3% to 97.1%).&#x0D; Conclusion: Effective antimicrobial stewardship programs must be in place in order to ensure the appropriate use of antibiotics for treating urinary tract infections.

Evidence and Molecular Characterization of Multidrug Resistant Staphylococcus aureus Isolated From Equines in Pakistan

The purpose of the current study was to investigate the nasal colonization and drug resistance profile of Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and vancomycin-resistant S. aureus (VRSA) in donkeys (n =63), mules (n=42), and horses (n=98). MRSA and VRSA were confirmed based on phenotypic and molecular methods, followed by phylogenetic analysis. Furthermore, the association of various animal and management-based risk factors with S. aureus colonization was also evaluated. The presence of nuc gene on polymerase chain reaction showed an overall prevalence of 42.86% of S. aureus in equines. Based on Kirby-Bauer disc diffusion test, 26.44% of isolates showed resistance to vancomycin. Further, mecA and vanB genes were targeted which showed an overall 14.94% and 13.79% prevalence of methicillin and vancomycin-resistant isolates, respectively. The phylogenetic analysis revealed a significant variation of the study isolates with each other and with already reported sequences of mecA and vanB genes. Risk factor analysis revealed that raising purpose (P=.011), work intensity (P < .001), stocking density (P=.006), presence of other livestock animals in surroundings (P=.043), and common drinking water source (P=.023) as significant. Antimicrobial susceptibility testing of MRSA and VRSA isolates showed high resistance to various commonly used antibiotics. Furthermore, all the tested isolates showing resistance to three or more than three antibiotics were considered multiple drug-resistant. The current study manifests the molecular evidence of MRSA and VRSA isolated from equines in Pakistan which will help to address the emerging issue of multidrug resistance in S. aureus in equines and emphasizes the need for possible measures to tackle this issue.

Antimicrobial Activity of Cosmos caudatus Against Staphylococcus aureus and Escherichia coli.

Malaysia is known for its richness in ecosystem including medicinal plants and herbs. The use of traditional herbs for medical purposes has been practiced for ages without any proper understanding on how they work. This study aims to produce extract from the leaves of Cosmos caudatus (Ulam Raja) and to investigate the antimicrobial activity of the produced extract against Staphylococcus aureus and Escherichia coli. Ethanolic Soxhlet extraction was carried out to obtain the leaves extract. Product from extraction process was subsequently tested using the Kirby-Bauer disk diffusion test to determine its inhibitory effects against S. aureus and E. coli. Finally, the bioactive compounds in extracts were profiled using gas chromatography coupled with mass spectrometer (GC-MS). Findings showed ethanol is suitable to be used in obtaining extract from the leaves of C. caudatus. The extract produced was dark green and was able to inhibit the growth of both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria. The size of inhibition zones ranging from 22 to 24 mm. The zones of inhibition produced by C. caudatus extract in this study are comparable to commercial antiseptic tested simultaneously in the experiment. Analysis of extract using GC-MS revealed several bioactive compounds including palmitic acid, stigmasterol, phytol and neophytadiene These compounds are well known for their medicinal and therapeutic properties such as antimicrobial, antioxidants and antitumor. Additionally, these bioactive compounds are commonly used as ingredients in commercial antiseptics and disinfectants. This study therefore has proven the medicinal properties of C. caudatus. Findings from this study can be used to develop plant-based pharmaceutical products which are cheaper, safer, and more environmentally friendly.

Trend of Changes in Chloramphenicol Resistance during the Years 2017–2020: A Retrospective Report from Israel

Resistant bacteria limit treatment options. This challenge has awakened interest in antibiotics that are no longer in use due to side effects, such as chloramphenicol. This work investigated trends in chloramphenicol resistance rates during 2017-2020 in bacteria isolated from diverse clinical samples at the Baruch Padeh Medical Center, Poriya, Israel. Bacteria were isolated from 3873 samples and identified using routine methods, including matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) technology. Chloramphenicol susceptibility was tested using a VITEK II instrument or by the Kirby-Bauer disk-diffusion test. The average chloramphenicol resistance rate was 24%, with no significant differences between study years. Chloramphenicol resistance was associated with sample origin (p < 0.001); isolates originating from sputum samples showed 49.8% resistance rate, compared to 2.3% of the body fluid isolates, 10.4% of the ear/eye isolates and 22.5% of the blood isolates. Furthermore, there was a significant decrease in chloramphenicol resistance among blood and ear/eye isolates during the study period (p = 0.01, p < 0.001, respectively). The highest resistance rate was among Pseudomonas aeruginosa isolates (50.5%). In conclusion, since chloramphenicol susceptibility seems to be retained, its comeback to the clinical world should be considered.