Probing nanomotion of single bacteria with graphene drums

AbstractMotion is a key characteristic of every form of life1. Even at the microscale, it has been reported that colonies of bacteria can generate nanomotion on mechanical cantilevers2, but the origin of these nanoscale vibrations has remained unresolved3,4. Here, we present a novel technique using drums made of ultrathin bilayer graphene, where the nanomotion of single bacteria can be measured in its aqueous growth environment. A single E. coli cell is found to generate random oscillations with amplitudes of up to 60 nm, exerting forces of up to 6 nN to its environment. Using mutant strains, we are able to pinpoint the bacterial flagella as the main source of nanomotion. By real-time tracing of changes in nanomotion upon administering antibiotics, we demonstrate that graphene drums can perform antibiotic susceptibility testing with single-cell sensitivity. These findings deepen our understanding of processes underlying cellular dynamics, and pave the way towards high throughput and parallelized rapid screening of the effectiveness of antibiotics in bacterial infections with graphene devices.

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Preliminary Study on Disinfectant Susceptibility/Resistance Profiles of Bacteria Isolated from Slaughtered Village Free-Range Chickens in Nairobi, Kenya

International Journal of Microbiology ◽

10.1155/2021/8877675 ◽

2021 ◽

Vol 2021 ◽

pp. 1-7

Author(s):

Igizeneza Acsa ◽

Bebora Lilly Caroline ◽

Nyaga Philip Njeru ◽

Njagi Lucy Wanjiru

Keyword(s):

Benzalkonium Chloride ◽

Bacterial Infections ◽

Susceptibility Testing ◽

Chlorhexidine Gluconate ◽

Bacterial Isolates ◽

E Coli ◽

Dimethyl Ammonium Chloride ◽

Dimethyl Ammonium ◽

Resistance Patterns ◽

Preliminary Study

Disinfectants are regularly used for cleansing poultry slaughterhouses to control microorganisms. However, the microorganisms such as bacteria are developing resistance to disinfectant(s) and complicate control of bacterial infections. The aim of this study was, therefore, to determine disinfectant susceptibility/resistance patterns manifested by bacteria (to commonly used disinfectants), which were isolated from intestines of slaughtered indigenous chickens in Nairobi, Kenya. The method used was agar well diffusion, and the six disinfectants (their active ingredients are in brackets) tested were as follows: Kupacide® (glutaraldehyde; benzalkonium chloride); TH4+® (didecyl dimethyl ammonium HCl; dioctyl dimethyl ammonium HCl; octyl decyldimethyl ammonium HCl; alkyl dimethyl ammonium HCl; and glutaraldehyde); Noro cleanse® (glutaraldehyde; coco-benzyl-dimethyl-ammonium chloride); Dettol® (chloroxylenol); Savlon® (chlorhexidine gluconate; cetrimide; and N-propylalcohol); and Jik® (sodium hypochlorite). At recommended user concentration by the manufacturer, isolates showed various resistance to the respective disinfectants. E. coli isolates were resistant to five of the tested disinfectants (Jik®, TH4+®, Noro cleanse®, Dettol®, and Kupacide®); however, they were susceptible to Savlon®; Staphylococcus isolates were resistant to disinfectants to Jik® and TH4+® and susceptible to the rest disinfectants; Streptococcus isolates were only resistant to Jik® and susceptible to the remaining disinfectants. Some E. coli and Staphylococcus isolates showed resistance to more than one disinfectant. This study has demonstrated resistance of the bacterial isolates to various disinfectants at recommended user concentrations, although some of them were susceptible at higher concentration(s) and lower concentrations. This will interfere with the cleansing of the respective premises, resulting in contaminated products, which may end-up causing disease in the humans consuming them. Hence, it is recommended that one ascertains the efficacy of respective disinfectant by carrying out disinfectant susceptibility testing to know the effective ones and the appropriate concentration to use.

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Characterization and Antimicrobial Susceptibility Profiles of Bacteria Isolated from Various Specimens among Mary Begg Health Facilities

International Journal of Health Sciences and Research ◽

10.52403/ijhsr.20210506 ◽

2021 ◽

Vol 11 (5) ◽

pp. 41-52

Author(s):

Stephen Mwisiya Mubita ◽

Wila Simbile ◽

Barbara Mulunda

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Antimicrobial Resistance ◽

Antimicrobial Susceptibility ◽

Bacterial Infections ◽

Susceptibility Testing ◽

Health Facilities ◽

Antimicrobial Susceptibility Testing ◽

E Coli ◽

Susceptibility Profiles

Background: The ever-increasing magnitude of antimicrobial resistance encountered in human pathogens has led to limited treatment options for bacterial infections, consequently reducing antimicrobial efficacy while increasing treatment costs, morbidity, and mortality. In clinical setup, laboratory-based in vitro antimicrobial susceptibility testing is the cornerstone for guiding therapy and enables the monitoring of antimicrobial resistance trends. Aim: To characterize the distribution of bacteria isolated from various specimens and their antibiotic susceptibility profiles in Mary Begg Health facilities. Material & Methods: This was a retrospective, cross-sectional, quantitative, descriptive study that involved the review of 569 laboratory files from three Mary Begg Health facilities from the period of January 2019 to June 2020. A systematic random sampling method was used and SPSS version 21.0 was used for data analysis. Results: The distribution of bacteria based on Gram stain reaction found that most bacteria that were isolated were Gram negative bacilli, 79.5% (171/215). The most common bacterium isolated was Escherichia coli, 46.5% (100/215) followed by Staphylococcus aureus, 12.1% (26/215) and Klebsiella pneumoniae, 17 7.9% (17/215). The study found that E. coli was highly resistant to amoxicillin (95.0%), Ampicillin (90.0%) and Cotrimoxazole (77.0%), respectively. In contrast, E. coli was highly sensitive to Amikacin (96.0%), Ertapenem (91.0%) and Ceftriaxone (80.0%) S. aureus species isolated were sensitive to Gentamicin (65.4%) and Clindamycin (46.2%) but highly resistant to Cotrimoxazole (80.8%). Conclusion: The most frequent isolates were Escherichia coli followed by Staphylococcus aureus and majority of them were from urine specimens. Key words: Antimicrobial, Resistant, Antimicrobial Resistance, Antimicrobial susceptibility testing, Mary Begg Health services.

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Bacterial detection and differentiation via direct volatile organic compound sensing with surface enhanced Raman spectroscopy

10.26434/chemrxiv.5393281 ◽

2017 ◽

Author(s):

Caitlin S. DeJong ◽

David I. Wang ◽

Aleksandr Polyakov ◽

Anita Rogacs ◽

Steven J. Simske ◽

...

Keyword(s):

Raman Spectroscopy ◽

Bacterial Infections ◽

Direct Detection ◽

Point Of Care ◽

Surface Enhanced Raman Spectroscopy ◽

E Coli ◽

Recent Emergence ◽

Surface Enhanced ◽

Volatile Organic ◽

Surface Enhanced Raman

Through the direct detection of bacterial volatile organic compounds (VOCs), via surface enhanced Raman spectroscopy (SERS), we report here a reconfigurable assay for the identification and monitoring of bacteria. We demonstrate differentiation between highly clinically relevant organisms: Escherichia coli, Enterobacter cloacae, and Serratia marcescens. This is the first differentiation of bacteria via SERS of bacterial VOC signatures. The assay also detected as few as 10 CFU/ml of E. coli in under 12 hrs, and detected E. coli from whole human blood and human urine in 16 hrs at clinically relevant concentrations of 103 CFU/ml and 104 CFU/ml, respectively. In addition, the recent emergence of portable Raman spectrometers uniquely allows SERS to bring VOC detection to point-of-care settings for diagnosing bacterial infections.

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Probiotics Slow the Growth of Pathogenic Bacteria

International Journal of Probiotics and Prebiotics ◽

10.37290/ijpp2641-7197.14:28-31 ◽

2019 ◽

Vol 14 (1) ◽

pp. 28-31 ◽

Cited By ~ 1

Author(s):

Rowles H. L.

Keyword(s):

Growth Rate ◽

Bacterial Infections ◽

Pathogenic Bacteria ◽

Diarrheal Disease ◽

Growth Curves ◽

Mortality Rates ◽

Controlled Delivery ◽

E Coli ◽

Multiple Strains ◽

Commercial Probiotics

Probiotics are live microorganisms, which when ingested in sufficient amounts, confer health benefits to the host by improving the gut microflora balance. The purpose of this research was to determine whether commercial probiotic products containing multitude of commensal bacteria would reduce the growth rate of pathogenic bacteria, specifically Escherichia coli and Salmonella typhimurium. Growth curves were established, and the growth rates were compared for samples of E. coli, S. typhimurium, Nature’s Bounty Controlled Delivery probiotic, Sundown Naturals Probiotic Balance probiotic, and cocultures of the pathogenic bacteria mixed with the probiotics. The findings of this research were that the commercial probiotics significantly reduced the growth rate of E. coli and S. typhimurium when combined in cocultures. Probiotics containing multiple strains may be taken prophylactically to reduce the risk of bacterial infections caused by E. coli and S. typhimurium. Probiotics could be used to reduce the high global morbidity and mortality rates of diarrheal disease.

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High prevalence of qnrA and qnrB genes among fluoroquinolone-resistant Escherichia coli isolates from a tertiary hospital in Southern Nigeria

Bulletin of the National Research Centre ◽

10.1186/s42269-020-00475-w ◽

2021 ◽

Vol 45 (1) ◽

Author(s):

Chibuzor M. Nsofor ◽

Mirabeau Y. Tattfeng ◽

Chijioke A. Nsofor

Keyword(s):

Escherichia Coli ◽

Susceptibility Testing ◽

Tertiary Hospital ◽

Vaginal Swab ◽

Fluoroquinolone Resistance ◽

E Coli ◽

Diffusion Technique ◽

High Prevalence ◽

Polymerase Chain ◽

And Control

Abstract Background This study was aimed to determine the prevalence of qnr genes among fluoroquinolone-resistant Escherichia coli (FREC) isolates from Nigeria. Antimicrobial susceptibility testing was performed by disc diffusion technique. Polymerase chain reaction was used to identify Escherichia coli (E. coli) and for the detection of qnr genes. Results A total of 206 non-duplicate E. coli were isolated from 300 clinical specimens analyzed. In all, 30 (14.6%) of these isolates were FREC; the resistance to fluoroquinolones among these 30 FREC showed 80% (24), 86.7% (26), 86.7% (26), 100% (30), 86.7% (26), 93.3% (28) and 86.7% (26) were resistant to pefloxacin, ciprofloxacin, sparfloxacin, levofloxacin, nalidixic acid, ofloxacin and moxifloxacin, respectively. The distribution of FREC among the various sample sources analyzed showed that 14%, 10%, 13.3%, 16.7% and 20% of the isolates came from urine, stool, high vaginal swab, endo cervical swab and wound swab specimens, respectively. More FREC were isolated from female samples 73.3% (22) compared to male samples 26.7% (8) and were more prevalent among the age group 26–35 years (40%). Twenty eight out of the 30 (93.3%) FREC isolates possessed at least one fluoroquinolone resistance gene in the form of qnrA 10 (33.3%) and qnrB 18 (60%), respectively; qnrS was not detected among the FREC isolates analyzed and 13.5% of the isolates possessed both the qnrA and qnrB genes. Phylogenetic analysis showed that these isolates were genetically diverse. Conclusions These findings suggest a possible resistance to fluoroquinolone is of high interest for better management of patients and control of antimicrobial resistance in Nigeria.

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Applicability and performance of EUCAST’s rapid antimicrobial susceptibility testing (RAST) on primarily sterile body fluids in blood culture bottles in laboratory routine with total lab automation

European Journal of Clinical Microbiology & Infectious Diseases ◽

10.1007/s10096-020-04146-6 ◽

2021 ◽

Author(s):

Jasmin Kaur Jasuja ◽

Stefan Zimmermann ◽

Irene Burckhardt

Keyword(s):

Blood Culture ◽

Susceptibility Testing ◽

Reference Method ◽

Body Fluids ◽

E Coli ◽

Mueller Hinton ◽

Mueller Hinton Agar ◽

And Performance ◽

Sterile Body Fluids ◽

Better Than

AbstractOptimisation of microbiological diagnostics in primarily sterile body fluids is required. Our objective was to apply EUCAST’s RAST on primarily sterile body fluids in blood culture bottles with total lab automation (TLA) and to compare results to our reference method Vitek2 in order to report susceptibility results earlier. Positive blood culture bottles (BACTEC™ Aerobic/Anaerobic/PEDS) inoculated with primarily sterile body fluids were semi-automatically subcultured onto Columbia 5% SB agar, chocolate agar, MacConkey agar, Schaedler/KV agar and Mueller-Hinton agar. On latter, cefoxitin, ampicillin, vancomycin, piperacillin/tazobactam, meropenem and ciprofloxacin were added. After 6 h, subcultures and RAST were imaged and MALDI-TOF MS was performed. Zone sizes were digitally measured and interpreted following RAST breakpoints for blood cultures. MIC values were determined using Vitek2 panels. During a 1-year period, 197 Staphylococcus aureus, 91 Enterococcus spp., 38 Escherichia coli, 11 Klebsiella pneumoniae and 8 Pseudomonas aeruginosa were found. Categorical agreement between RAST and MIC was 96.5%. Comparison showed no very major errors, 2/7 (28.6%) and 1/7 (14.3%) of major errors for P. aeruginosa and meropenem and ciprofloxacin, 1/9 (11.1%) for K. pneumoniae and ciprofloxacin, 4/69 (7.0%) and 3/43 (5.8%) for Enterococcus spp. and vancomycin and ampicillin, respectively. Minor errors for P. aeruginosa and meropenem (1/8; 12.8%) and for E. coli and ciprofloxacin (2/29; 6.5%) were found. 30/550 RAST measurements were within area of technical uncertainty. RAST is applicable and performs well for primarily sterile body fluids in blood culture bottles, partially better than blood-based RAST. Official EUCAST evaluation is needed.

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Evaluation of commercially available aroA delated gene E. coli O78 vaccine in commercial broiler chickens under Middle East simulating field conditions

Scientific Reports ◽

10.1038/s41598-021-81523-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Hussein M. Galal ◽

M. I. Abdrabou ◽

Ahmed H. I. Faraag ◽

C. K. Mah ◽

Azza M. Tawfek

Keyword(s):

Middle East ◽

Broiler Chickens ◽

Bacterial Infections ◽

Body Weight Gain ◽

Broiler Chicks ◽

E Coli ◽

Reduced Body ◽

Antibiotics Use ◽

Commercial Broiler ◽

And Performance

AbstractThe broiler industry in the Middle East (ME) faces many challenges related to bacterial infections, including M. gallisepticum, M. synoviae, E. coli, and other gram-negative bacteria, exacerbated by various errors in the brooding process. Antibiotics use in the first three days of life, such as Linco-Spectin 100 SP, tilmicosin, enrofloxacin, tylosin, colistin, and doxycycline, is the trend in the market to control such challenges. This study aimed to evaluate the efficacy of the newly introduced aroA E. coli vaccine (Poulvac E. coli) and its ability to reduce over-reliance on the heavy use of antibiotics in the ME. The study was conducted on 160 broiler chicks, divided into eight even groups. Each group was treated differently in terms of antibiotic therapy and ages at the time of Poulvac E. coli administration and the challenge of virulent avian pathogenic E. coli (APEC), serotype O78. Spray application of Poulvac E. coli at seven days of age plus Linco-Spectin 100 SP during the first three days provided the best results for zero mortality after challenge with APEC, while Poulvac E. coli at seven days with enrofloxacin during the early three days resulted in 10% mortality. Poulvac E. coli hatchery vaccination protected birds against mortality but reduced body weight gain compared to the 7-day group vaccinated with Linco-Spectin 100 SP during the first three days. Poulvac E. coli given on day one or day seven did not affect the immune response to concurrent respiratory viral vaccines and, in some cases, improved response. This study shows that Poulvac E. coli at seven days of age, together with Linco-Spectin 100 during the first three days, has produced the best results in terms of protection and performance in the ME high presence of avian pathogenic E. coli field challenge.

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Three-Year Trend in Escherichia coli Antimicrobial Resistance among Children’s Urine Cultures in an Italian Metropolitan Area

Children ◽

10.3390/children8070597 ◽

2021 ◽

Vol 8 (7) ◽

pp. 597

Author(s):

Luca Pierantoni ◽

Laura Andreozzi ◽

Simone Ambretti ◽

Arianna Dondi ◽

Carlotta Biagi ◽

...

Keyword(s):

Escherichia Coli ◽

Metropolitan Area ◽

Bacterial Infections ◽

Asymptomatic Bacteriuria ◽

Multidrug Resistant ◽

Resistance Rate ◽

First Line ◽

E Coli ◽

First Line Therapy ◽

Tract Infections

Urinary tract infections (UTIs) are among the most common bacterial infections in children, and Escherichia coli is the main pathogen responsible. Several guidelines, including the recently updated Italian guidelines, recommend amoxicillin-clavulanic acid (AMC) as a first-line antibiotic therapy in children with febrile UTIs. Given the current increasing rates of antibiotic resistance worldwide, this study aimed to investigate the three-year trend in the resistance rate of E. coli isolated from pediatric urine cultures (UCs) in a metropolitan area of northern Italy. We conducted a retrospective review of E. coli-positive, non-repetitive UCs collected in children aged from 1 month to 14 years, regardless of a diagnosis of UTI, catheter colonization, urine contamination, or asymptomatic bacteriuria. During the study period, the rate of resistance to AMC significantly increased from 17.6% to 40.2% (p < 0.001). Ciprofloxacin doubled its resistance rate from 9.1% to 16.3% (p = 0.007). The prevalence of multidrug-resistant E. coli rose from 3.9% to 9.2% (p = 0.015). The rate of resistance to other considered antibiotics remained stable, as did the prevalence of extended spectrum beta-lactamases and extensively resistant E. coli among isolates. These findings call into question the use of AMC as a first-line therapy for pediatric UTIs in our population, despite the indications of recent Italian guidelines.

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Interaction of Temporin-L Analogues with the E. coli FtsZ Protein

Antibiotics ◽

10.3390/antibiotics10060704 ◽

2021 ◽

Vol 10 (6) ◽

pp. 704

Author(s):

Angela Di Somma ◽

Carolina Canè ◽

Antonio Moretta ◽

Angela Duilio

Keyword(s):

Protein Interactions ◽

Bacterial Infections ◽

Antibacterial Properties ◽

Bacterial Cell Division ◽

Structural Determinants ◽

E Coli ◽

Functional Studies ◽

Division Process ◽

Z Ring ◽

Peptide Complexes

The research of new therapeutic agents to fight bacterial infections has recently focused on the investigation of antimicrobial peptides (AMPs), the most common weapon that all organisms produce to prevent invasion by external pathogens. Among AMPs, the amphibian Temporins constitute a well-known family with high antibacterial properties against Gram-positive and Gram-negative bacteria. In particular, Temporin-L was shown to affect bacterial cell division by inhibiting FtsZ, a tubulin-like protein involved in the crucial step of Z-ring formation at the beginning of the division process. As FtsZ represents a leading target for new antibacterial compounds, in this paper we investigated in detail the interaction of Temporin L with Escherichia coli FtsZ and designed two TL analogues in an attempt to increase peptide-protein interactions and to better understand the structural determinants leading to FtsZ inhibition. The results demonstrated that the TL analogues improved their binding to FtsZ, originating stable protein-peptide complexes. Functional studies showed that both peptides were endowed with a high capability of inhibiting both the enzymatic and polymerization activities of the protein. Moreover, the TL analogues were able to inhibit bacterial growth at low micromolar concentrations. These observations may open up the way to the development of novel peptide or peptidomimetic drugs tailored to bind FtsZ, hampering a crucial process of bacterial life that might be proposed for future pharmaceutical applications.

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Mechanistic insights into synergy between nalidixic acid and tetracycline against clinical isolates of Acinetobacter baumannii and Escherichia coli

Communications Biology ◽

10.1038/s42003-021-02074-5 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Amit Gaurav ◽

Varsha Gupta ◽

Sandeep K. Shrivastava ◽

Ranjana Pathania

Keyword(s):

Escherichia Coli ◽

Acinetobacter Baumannii ◽

Nalidixic Acid ◽

Bacterial Infections ◽

Clinical Isolates ◽

Hospital Environment ◽

Infection Model ◽

Drug Resistant ◽

E Coli

AbstractThe increasing prevalence of antimicrobial resistance has become a global health problem. Acinetobacter baumannii is an important nosocomial pathogen due to its capacity to persist in the hospital environment. It has a high mortality rate and few treatment options. Antibiotic combinations can help to fight multi-drug resistant (MDR) bacterial infections, but they are rarely used in the clinics and mostly unexplored. The interaction between bacteriostatic and bactericidal antibiotics are mostly reported as antagonism based on the results obtained in the susceptible model laboratory strain Escherichia coli. However, in the present study, we report a synergistic interaction between nalidixic acid and tetracycline against clinical multi-drug resistant A. baumannii and E. coli. Here we provide mechanistic insight into this dichotomy. The synergistic combination was studied by checkerboard assay and time-kill curve analysis. We also elucidate the mechanism behind this synergy using several techniques such as fluorescence spectroscopy, flow cytometry, fluorescence microscopy, morphometric analysis, and real-time polymerase chain reaction. Nalidixic acid and tetracycline combination displayed synergy against most of the MDR clinical isolates of A. baumannii and E. coli but not against susceptible isolates. Finally, we demonstrate that this combination is also effective in vivo in an A. baumannii/Caenorhabditis elegans infection model (p < 0.001)

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