Emergence of high multidrug-resistant Escherichia coli isolates from neonates with infection

Abstract Background Escherichia coli (E.coli) rank one of the most common pathogens that can cause neonatal infections. The emergence of antibiotic-resistant bacteria is a major cause of treatment failure in newborn with infection. The purpose of this study was to describe the antibiotic resistance and multidrug-resistance of E.coli isolated from neonates with infection.Methods The antimicrobial susceptibility testing of the E. coli strains to selected antibiotics was assessed with the E-test technique on the Mueller-Hinton agar. The antimicrobials tests were included ceftazidime, cefuroxime, cefatriaxone, amoxicillin, amoxicillin-clavulanic acid, cefoperazone - sulbactam, meropenem, gentamicin, ciprofloxacin and sulfonamides. The minimal inhibitory concerntration (MIC) values of the antimicrobial agents selected for this study was determined by an agar dilution technique on Mueller-Hinton agar according to the Clinical and Laboratory Standards Institute recommendations. Results A total of 100 E. coli strains was isolated from phlegm (n = 78), blood (n = 10), cerebrospinal fluid (n = 5), and umbilical discharge (n = 7) of neonates hospitalized at Beijing Children’s Hospital. The highest resistance rate of E.coli was found in amoxicillin at 85%, followed by cefuroxime 65%, and cefatriaxone 60%, respectively. 6% and 5% of all isolates were resistant to amoxicillin/clavulanic acid and cefoperazone -sulbactam merely. The resistance rates to ceftazidime, gentamicin, ciprofloxacin and sulfonamides were 31%, 20%, 33%, 47%, respectively. All the isolates were susceptible to meropenem. Multidrug resistance was defined in E.coli as resistance to at least three antibiotic families. About 26% (26/100) of all the E.coli isolates were multidrug-resistant. The detection rate of ESBL-Producing E. coli was 55%. The rate in E. coli isolates from phlegm was higher than aseptic humoral. The difference was statistically significant (P < 0.05). It is worth noting that the majority of the isolates were also resistant to non-β-lactam antimicrobial agents, but the resistant rates were significantly lower than extended-spectrum β-lactamases.Conclusions: Multi-drug-resistant E.coli has become a thorny problem in clinical treatment. It is necessary to monitor E. coli resistance.

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Antimicrobial Resistance Analysis of Clinical Escherichia coli Isolates in Neonatal Ward

Frontiers in Pediatrics ◽

10.3389/fped.2021.670470 ◽

2021 ◽

Vol 9 ◽

Author(s):

Dan Wu ◽

Yijun Ding ◽

Kaihu Yao ◽

Wei Gao ◽

Yajuan Wang

Keyword(s):

Escherichia Coli ◽

Clavulanic Acid ◽

Multidrug Resistant ◽

Complex Problem ◽

Resistant Bacteria ◽

Test Technique ◽

E Coli ◽

Mueller Hinton ◽

Mueller Hinton Agar ◽

Amoxicillin Clavulanic Acid

Background:Escherichia coli (E. coli) column for one of the most common pathogens causing neonatal infections. The emergence of antibiotic-resistant bacteria is a major cause of treatment failure in infected newborns. The purpose of this study was to describe antibiotic and multidrug resistance of E. coli strains isolated from neonates with infection throughout the years 2009–2011.Methods: The antimicrobial susceptibility testing of E. coli strains to selected antibiotics was assessed using the E-test technique on the Mueller-Hinton agar. The antimicrobial tests included ceftazidime, cefuroxime, cefatriaxone, amoxicillin, amoxicillin-clavulanic acid, cefoperazone- sulbactam, meropenem, gentamicin, ciprofloxacin, and sulfonamides.Results: A total of 100 E. coli strains were isolated from sputum (n = 78), blood (n = 10), cerebrospinal fluid (n = 5), and umbilical discharge (n = 7) samples of hospitalized neonates at the Beijing Children's Hospital. The highest rate of E. coli resistance was found in amoxicillin (85%), followed by cefuroxime (65%), and cefatriaxone (60%), respectively. A total of 6 and 5% of all isolates were only resistant to amoxicillin/clavulanic acid and cefoperazone -sulbactam. The rates of resistance to ceftazidime, gentamicin, ciprofloxacin, and sulfonamides were 31, 20, 33, and 47%, respectively. All isolates were susceptible to meropenem. Approximately 26% of all E. coli isolates were multidrug-resistant. The detection rate of ESBL-Producing E. coli was 55%.Conclusions: Multi-drug-resistant E. coli has become an important and complex problem in clinical treatment, and it is thus essential to monitor E. coli resistance in neonates.

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Escherichia coli ATCC 35218 as a Quality Control Isolate for Susceptibility Testing of Haemophilus influenzae with Haemophilus Test Medium

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.43.2.283 ◽

1999 ◽

Vol 43 (2) ◽

pp. 283-286 ◽

Cited By ~ 5

Author(s):

D. L. Butler ◽

C. J. Jakielaszek ◽

L. A. Miller ◽

J. A. Poupard

Keyword(s):

Escherichia Coli ◽

Quality Control ◽

Clavulanic Acid ◽

Susceptibility Testing ◽

Test Medium ◽

E Coli ◽

Mueller Hinton ◽

Quality Control Testing ◽

Amoxicillin Clavulanic Acid ◽

Lactamase Inhibitor

ABSTRACT Current National Committee for Clinical Laboratory Standards (NCCLS) susceptibility guidelines for quality control testing withHaemophilus influenzae do not include a β-lactamase-producing strain that could detect the deterioration of the β-lactamase inhibitor components of amoxicillin-clavulanic acid, ampicillin-sulbactam, and piperacillin-tazobactam. The objective of the study was to determine if comparable quality control results forEscherichia coli ATCC 35218, a β-lactamase-producing strain, would be produced for the three β-lactam–β-lactamase inhibitor agents with Haemophilus test medium and Mueller-Hinton medium. The criteria used in this study to determine if Haemophilus test medium was acceptable for quality control testing of E. coli ATCC 35218 was that 100% of the results obtained with an antimicrobial agent-methodology combination needed to be within the acceptable NCCLS ranges established with Mueller-Hinton medium. The MIC testing results obtained by the broth microdilution and E-test methods with amoxicillin-clavulanic acid and piperacillin-tazobactam were all within the NCCLS ranges; however, the results obtained with ampicillin-sulbactam by both methods were not within the NCCLS ranges. Acceptable results were obtained by the disk diffusion methodology with ampicillin-sulbactam and piperacillin-tazobactam but not with amoxicillin-clavulanic acid. When performing susceptibility testing with H. influenzae with the β-lactam–β-lactamase inhibitors, in addition to quality control testing with H. influenzae ATCC 49247, testing of E. coli ATCC 35218 on Haemophilus test medium is an effective way to monitor the β-lactamase inhibitors in some antimicrobial agent-methodology combinations.

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Drug Susceptibility Testing and Synergistic Antibacterial Activity of Curcumin with Antibiotics against Enterotoxigenic Escherichia coli

Antibiotics ◽

10.3390/antibiotics8020043 ◽

2019 ◽

Vol 8 (2) ◽

pp. 43 ◽

Cited By ~ 3

Author(s):

Rangel-Castañeda Itzia Azucena ◽

Cruz-Lozano José Roberto ◽

Zermeño-Ruiz Martin ◽

Cortes-Zarate Rafael ◽

Hernández-Hernández Leonardo ◽

...

Keyword(s):

Escherichia Coli ◽

Clavulanic Acid ◽

Susceptibility Testing ◽

Drug Susceptibility ◽

Drug Susceptibility Testing ◽

Enterotoxigenic Escherichia Coli ◽

Antimicrobial Drugs ◽

Mueller Hinton ◽

Mueller Hinton Agar ◽

Amoxicillin Clavulanic Acid

Aim: This study investigated the susceptibility of Enterotoxigenic Escherichia coli to curcumin, as well as its synergistic effect with 12 antimicrobial drugs. Methods and Results: Our study shows that curcumin did not affect bacterial growth. The antimicrobial susceptibility of curcumin and antibiotic synergy were identified using disc diffusion on Mueller-Hinton agar. The strain of Enterotoxigenic Escherichia coli used was resistant to Ampicillin, Amoxicillin/Clavulanic acid, Ampicillin/Sulbactam, Ciprofloxacin, and Cefazolin. There was synergy between curcumin and the majority of antibiotics tested. Maximum synergy was observed with combinations of 330 µg/mL curcumin and Ceftazidime, followed by Cefotaxime, Amoxicillin/Clavulanic acid, Ampicillin, Aztreonam, Trimethoprim, Ciprofloxacin, Ceftriaxone, Cefazolin, Tetracycline, and Imipenem. Conclusion: Our findings indicated that curcumin might be useful as a combinatorial strategy to combat the antibiotic resistance of Enterotoxigenic Escherichia coli.

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611. Fosfomycin Resistance of Multidrug-Resistant Escherichia coli and Mechanisms of Fosfomycin Resistance

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.680 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S285-S285

Author(s):

Hyeri Seok ◽

Ji Hoon Jeon ◽

Hee Kyoung Choi ◽

Won Suk Choi ◽

Dae Won Park ◽

...

Keyword(s):

Escherichia Coli ◽

Antimicrobial Agents ◽

Multidrug Resistant ◽

Resistance Rate ◽

Coli Strain ◽

Resistant Bacteria ◽

E Coli ◽

Broth Microdilution Method ◽

Fosfomycin Resistance

Abstract Background Fosfomycin is one of the antibiotics that may be a candidate for the next-generation antimicrobial agents againt multidrug-resistant bacteria. To date, it is known that the resistance rate is not high for Escherichia coli. However, it is necessary to update the fosfomycin resistance rates in E. coli according to the studies that extended spectrum β-lactamase (ESBL) producing E. coli strains are highly resistance to fosfomycin. We evaluated the resistance rate of fosfomycin, the resistant mechanism of fosfomycin in E. coli, and the activity of fosfomycin against susceptible and resistant strains of E. coli. Methods A total of 283 clinical isolates was collected from patients with Escherichia coli species during the period of January 2018 to June 2018, in three tertiary hospitals of Republic of Korea. In vitro antimicrobial susceptibility tests were performed in all E. coli isolates using the broth microdilution method according to the Clinical and Laboratory Standard Institute (CLSI). Multilocus sequence typing (MLST) of the Oxford scheme was conducted to determine the genotypes of E. coli isolated. Fosfomycin genes were investigated for all fosfomycin-resistant E. coli strains. Results The overall resistance rate to fosfomycin was 10.2%, compared with 53.4%, 46.3%, 41.3%, 31.1%, 10.6%, 2.5%, and 2.1% for ciprofloxacin, cefixime, cefepime, piperacillin/tazobactam, colistin, ertapenem, and amikacin, respectively. The 29 fosfomycin-resistant isolates did not show a clonal pattern on the phylogenetic tree. MurA and glp genes were identified in all strains. FosA3 were identified in two strains and uhp gene were identified in 4 strains. In time-kill curve studies, fosfomycin was more bactericidal than cefixime against all sensitive E. coli strain. Morever, fosfomycin was more bactericidal than piperacillin/tazobactam against ESBL-producing E. coli strain. Conclusion The resistant rate of fosfomycin to E. coli is still low. Fosfomycin was active against E. coli including ESBL producing strains. Disclosures All authors: No reported disclosures.

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Beta-Lactamase-Producing Escherichia coli Isolates Recovered from Pig Handlers in Retail Shops and Abattoirs in Selected Localities in Southern Nigeria: Implications for Public Health

Antibiotics ◽

10.3390/antibiotics10010009 ◽

2020 ◽

Vol 10 (1) ◽

pp. 9

Author(s):

Olivia Sochi Egbule ◽

Benson C. Iweriebor ◽

Edward Ikenna Odum

Keyword(s):

Escherichia Coli ◽

Clavulanic Acid ◽

Multidrug Resistant ◽

Beta Lactamase ◽

Extended Spectrum Beta Lactamase ◽

E Coli ◽

Resistance Evolution ◽

Resistance Patterns ◽

Amoxicillin Clavulanic Acid ◽

And Gender

Antibiotic resistance evolution among pathogenic microorganisms has become a huge burden globally as it has increased the burden of diseases amongst humans and animals. The prevalence of extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-Ec) and metallo beta-lactamase-producing Escherichia coli (MBL-Ec) isolated from pig abattoir and handlers in retail shops was studied. In addition, the relationship between the isolates’ prevalence and the background characteristics of the butchers/retailers was also investigated. Samples from 32 hand swabs of pork sellers at retail shops and 8 butchers at abattoirs, as well as 272 swabs taken from knives, tables, floors, water troughs, and carcasses from both retail shops and abattoirs, were collected. Escherichia coli (E. coli) was isolated from hand swabs, fomites, and carcasses and were identified by standard microbiological procedures. The isolates susceptibility to nitrofurantoin (300 µg), ciprofloxacin (5 µg), ceftazidime (30 µg), cefuroxime (30 µg), gentamicin (10 µg), cefixime (5 µg), ofloxacin (5 µg), amoxicillin/clavulanic acid (30 µg), imipenem (10 µg), and meropenem (10 µg) and their ability to produce ESBL and MBL was determined by phenotypic methods. Demographic information of the handlers was retrieved by means of a structured questionnaire and, in some cases, via face to face interviews. Out of 104 E. coli isolates from both sources, 52 (50.0%) and 8 (7.7%) were ESBL and MBL producers, respectively. ESBL was more prevalent on the hands of the retailers (40.6%) and butchers (75.0%). The isolates were 100% resistant to ceftazidime, cefotaxime, and amoxicillin–clavulanic acid and 4.8% resistant to nitrofurantoin. Diverse resistance patterns were observed among ESBL-Ec and MBL-Ec. It was found that 90% of ESBL-Ec and 100% of MBL-Ec were multidrug-resistant. A possible epidemiological link between the two sources was observed. The prevalence of E. coli ESBL- and MBL-producing isolates was associated with the duty performed by handlers (p = 0.012) and gender (p = 0.012). Our results provide evidence that the handlers’ hands and abattoir environment had a great role to play in the high prevalence and resistance profiles of the microorganisms.

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Molecular Characterization of Multidrug-Resistant Escherichia coli Isolates from Edible Offal in Korea

Journal of Food Protection ◽

10.4315/0362-028x.jfp-18-458 ◽

2019 ◽

Vol 82 (7) ◽

pp. 1183-1190

Author(s):

SE HYUN SON ◽

KWANG WON SEO ◽

YEONG BIN KIM ◽

HYE YOUNG JEON ◽

EUN BI NOH ◽

...

Keyword(s):

Escherichia Coli ◽

Antimicrobial Resistance ◽

Virulence Genes ◽

Antimicrobial Agents ◽

Food Product ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

E Coli ◽

Antimicrobial Resistance Genes ◽

Class 1

ABSTRACT Edible offal, which is the nonmuscular part of the livestock, is a popular food product in many countries. However, it can be easily contaminated by bacteria, such as Escherichia coli, during slaughter and processing and regarded as a reservoir for transfer of antimicrobial-resistant bacteria to humans. This study aimed to investigate prevalence and characteristics of antimicrobial-resistant E. coli isolates from edible offal in Korea. A total of 320 chicken offal samples, 540 pig offal samples, and 560 cattle offal samples were collected. Among the 118 E. coli isolates obtained, resistance to at least one antimicrobial agent was revealed in 32 (100%), 46 (95.8%), and 26 (68.4%) isolates of chicken, pig, and cattle offals, respectively, with an overall prevalence of 88.1% (104 of 118). The isolates from chicken offal showed highest resistance to most antimicrobial agents, with the exception of higher ampicillin resistance for isolates from pig offal. In the distribution of antimicrobial resistance genes of 69 (58.5%) multidrug-resistant (MDR) E. coli, blaTEM-1 (97.1%), tetA (76.6%), sul2 (70.6%), and cmlA (57.4%) were most prevalent. Class 1 and class 2 integrons were detected in 82.6 and 2.9% of the MDR isolates, respectively. In total, seven virulence genes (eaeA, escV, astA, fimH, papC, sfa/focDE, and iucC) were also identified in the MDR isolates. The fimH gene was the most frequent (91.3%). Overall, 52 isolates from chicken (24 isolates, 96.0%), pig (16 isolates, 55.2%) and cattle (12 isolates, 80.0%) offals among MDR isolates were found to have some plasmid replicons. Frep (38 isolates) and FIB (27 isolates) replicons were more prevalent than other replicon types. The results suggest that edible offal can become a relevant reservoir of E. coli strains carrying various antimicrobial resistance and virulence genes. HIGHLIGHTS

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Effects of the prebiotic lactoferrin on multidrug-resistant Escherichia coli infections in broiler chickens

Veterinary World ◽

10.14202/vetworld.2021.2197-2205 ◽

2021 ◽

pp. 2197-2205

Author(s):

Heba Badr ◽

Nehal M. Nabil ◽

Maram M. Tawakol

Keyword(s):

Escherichia Coli ◽

Multidrug Resistance ◽

Broiler Chickens ◽

Antimicrobial Agents ◽

Multidrug Resistant ◽

Broiler Chicks ◽

Serum Samples ◽

Isolation And Identification ◽

E Coli ◽

Significant Difference

Background and Aim: Increased multidrug resistance in Escherichia coli has created challenges for the poultry industry. Consequently, new antimicrobial agents should preferentially be utilized for the prevention and treatment of E. coli outbreaks. This study aimed to evaluate the effects of lactoferrin (LF) as a prebiotic on broiler chicks challenged with multidrug-resistant E. coli in comparison with antibiotics. Materials and Methods: A total of 70 diseased flocks from Egypt were collected for E. coli isolation and identification, serotyping, and antimicrobial susceptibility pattern determination. E. coli was isolated and characterized phenotypically and one isolate that showed multidrug-resistance was selected. A challenge trial was performed to evaluate the effectiveness of LF as a prebiotic on the isolated multidrug-resistant E. coli. Liver samples were collected from the experimental chicks and subjected to E. coli enumeration to illustrate the effectiveness of LF on the liver cells and bacteria using an electron microscope. Serum samples were also collected to estimate lysozyme and nitric oxide (NO) concentrations. Results: After isolation of E. coli with a percentage of 54.3% from the diseased broilers, the strain was serotyped (identified serotypes: O2, O18, O55, O78, O86a, O111, O125, O126, O127, O157, O159, and O166). Multi-antibiotic resistance was found to be harbored in a high percentage among 11 antibiotic discs. The LF in the prophylactic and treated groups was found to have a significant effect in comparison with the group treated with the drug of choice (ciprofloxacin). Furthermore, a significant difference in the NO (one of non-specific immune response) and a non-significant difference in lysozyme concentrations were reported in the group fed on rations with LF in comparison with the non-fed group. Conclusion: LF was thus identified as an effective prebiotic that can improve chick performance, help them to overcome multidrug-resistant E. coli and stimulate immunity.

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AKTIVITAS ANTIBAKTERI ACTINOMYCETES ASAL DESA CEMPAKA KAPUAS HULU KALIMANTAN BARAT TERHADAP ENTEROPATOGENIK GASTROENTERITIS

AL-Kauniyah Jurnal Biologi ◽

10.15408/kauniyah.v13i1.11731 ◽

2020 ◽

Vol 13 (1) ◽

pp. 20-30

Author(s):

Abdullah Abdullah ◽

Ihsan Almuhardi ◽

Antoni Antoni ◽

Rahmawati Rahmawati

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Salmonella Enterica ◽

Pathogenic Bacteria ◽

Rice Fields ◽

Resistant Bacteria ◽

E Coli ◽

Mueller Hinton ◽

Nocardia Sp ◽

Mueller Hinton Agar

AbstrakAntibiotik yang digunakan secara tidak tepat dapat meningkatkan jumlah bakteri penyebab gastroenteritis yang resisten terhadap antibiotik. Beberapa kelompok mikroorganisme tanah diketahui memiliki potensi menghasilkan senyawa aktif untuk menghambat dan membunuh bakteri patogen, seperti Actinomycetes. Tujuan dari penelitian ini adalah untuk mengetahui potensi antibiotik Actinomycetes terhadap bakteri penyebab gastroenteritis yang diisolasi dari sawah tandus di Desa Cempaka Baru, Kabupaten Kapuas Hulu, Kalimantan Barat. Proses penelitian dilakukan dari isolasi Actinomycetes dari sawah tandus, karakterisasi, serta pengujian kemampuan antibiotik terhadap bakteri Escherichia coli ATCC 25922, Salmonella enterica ATCC 14028 dan Staphylococcus aureus ATCC 25923 menggunakan metode sumuran pada media Mueller Hinton Agar. Hasil identifikasi berdasarkan karakteristik morfologi koloni, sel, dan biokimia diperoleh 1 isolat bakteri, yaitu genus Nocardia sp. ATS-4.1 yang mampu menghambat pertumbuhan bakteri-bakteri uji yang dibuktikan adanya rata-rata zona hambat yang terbentuk, yakni 14,51 mm; 16,16 mm; dan 11,10 mm. Hasil uji statistik Friedman diperoleh nilai Asymp. Sig 0,10>0,05, sehingga menunjukkan bahwa pemberian cairan kultur isolat Nocardia ATS-4.1 memberikan pengaruh yang tidak berbeda nyata antara hambatan terhadap bakteri E. coli, S. enterica, dan S. aureus. Hal ini dapat disimpulkan bahwa isolat Nocardia sp. ATS-4.1 berpotensi menghasilkan antibakteri yang setara terhadap bakteri E. coli, S. enterica, dan S. aureus penyebab gastroenteritis.Abstract Using antibiotics incorrectly increases the number of resistant bacteria to gastroenteritis. Soil microorganisms are known to have the potential to produce active compounds to inhibit and kill pathogenic bacteria, for example, Actinomycetes. The purpose of this study was to determine the potential of antibiotics Actinomycetes isolated from rice fields in Cempaka Baru, Kapuas Hulu Regency, West Kalimantan, against gastroenteritis bacteria. The research order was carried out by isolating Actinomycetes from barren rice fields, and then characterizing and testing the ability of antibiotics against Escherichia coli ATCC 25922, Salmonella enterica ATCC 14028, and Staphylococcus aureus ATCC 25923 using the well method on Mueller Hinton Agar. The identification results based on morphological characteristics of colonies, cells and biochemistry showed that one of the bacteria was from genus Nocardia sp. ATS-4.1 which was able to inhibit the three test bacteria by the average inhibition zone 14.51 mm; 16.16 mm; and 11.10 mm, respectively. Friedman’s statistical test resulted in values asymp. sig 0.10>0.05 which showed that the isolate gave inhibition differences insignificantly among the bacteria. In conclusion, isolate Nocardia sp. ATS-4.1 able to produce equal antibacterial activity against bacteria E. coli, S. enterica and S. aureus caused gastroenteritis.

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Characterisation of Extended β-Lactamases and Plasmid Mediated Quinolones Resistancein Escherichia Coli from Shelter Dogs

Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca Veterinary Medicine ◽

10.15835/buasvmcn-vm:2019.0003 ◽

2019 ◽

Vol 76 (1) ◽

pp. 100

Author(s):

Andreea Paula COZMA ◽

Elena Iuliana MĂCIUCĂ ◽

Cătălin CARP-CĂRARE ◽

Mihai CARP-CĂRARE ◽

Cristina RÎMBU ◽

...

Keyword(s):

Escherichia Coli ◽

E Coli ◽

North East ◽

The North ◽

Extended Spectrum ◽

Mueller Hinton ◽

Genes Encoding ◽

Mueller Hinton Agar ◽

Amoxicillin Clavulanic Acid ◽

Shelter Dogs

The aim of this study was to determine the prevalence of β-lactamase (TEM, SHV, OXA), extended-spectrum β-lactamase (ESBL) and genes encoding plasmid mediated resistance to quinolones (PMQR) in extended spectrum cephalosporin (ESC)-resistant Escherichia coli isolated from dog faeces from two shelters in the North-East of Romania. Eighty-eight faecal samples from healthy dogs were analysed by cultivation on Brilliance ESBL medium (Oxoid, UK), followed by phenotipic ESBL screening using combination disc test (CDT). Identification of the E. coli strains was performed by uidA/uspA gene PCR. Susceptibility testing was performed on Mueller-Hinton Agar, with β-lactam and non-β-lactam agents. Identification of β-lactamase genes (blaCTX-M, blaTEM, blaSHV, blaOXA) and PMQR genes (qnrA, qnrB and qnrS) was performed by PCR as previously described. Twenty eight ESC-resistant E. coli (31.81%) were obtained and (n=21/28, 75%) of these were confirmed as ESBLs and showed resistance to cefpodoxime (n=21/28, 75%), amoxicillin/clavulanic acid (n=19/21; 90.48%), and enrofloxacin (n=8/21; 38.09%). Predominant ESBL types were CTX-M-1 (n=15/17, 88.24%) and CTX-M-9 (n=2/17, 11.76%) enzymes. TEM and SHV enzymes were identified in 17.86% and 14.29% of the ESC-resistant isolates, whilst some isolates (n=4) carried only blaTEM and blaSHV. The prevalence of PMQR genes was 28.57% of the 28 ESC resistant isolates, consisting of qnrS (62.5%) and qnrB (37.5%). These findings indicate a high prevalence of ESBLs and PMQR associated resistance E. coli in the normal faecal microbiota of dogs from shelters, which carries the risk for dissemination of these resistance genes to other animals, human or the environment.

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In vitro activity of antimicrobial peptide CDP-B11 alone and in combination with colistin against colistin-resistant and multidrug-resistant Escherichia coli

Scientific Reports ◽

10.1038/s41598-021-81140-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Kaitlin S. Witherell ◽

Jason Price ◽

Ashok D. Bandaranayake ◽

James Olson ◽

Douglas R. Call

Keyword(s):

Escherichia Coli ◽

Antimicrobial Peptide ◽

Membrane Integrity ◽

Antibiotic Resistance Genes ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

Multidrug Resistant Bacteria ◽

E Coli ◽

Minimal Media

AbstractMultidrug-resistant bacteria are a growing global concern, and with increasingly prevalent resistance to last line antibiotics such as colistin, it is imperative that alternative treatment options are identified. Herein we investigated the mechanism of action of a novel antimicrobial peptide (CDP-B11) and its effectiveness against multidrug-resistant bacteria including Escherichia coli #0346, which harbors multiple antibiotic-resistance genes, including mobilized colistin resistance gene (mcr-1). Bacterial membrane potential and membrane integrity assays, measured by flow cytometry, were used to test membrane disruption. Bacterial growth inhibition assays and time to kill assays measured the effectiveness of CDP-B11 alone and in combination with colistin against E. coli #0346 and other bacteria. Hemolysis assays were used to quantify the hemolytic effects of CDP-B11 alone and in combination with colistin. Findings show CDP-B11 disrupts the outer membrane of E. coli #0346. CDP-B11 with colistin inhibits the growth of E. coli #0346 at ≥ 10× lower colistin concentrations compared to colistin alone in Mueller–Hinton media and M9 media. Growth is significantly inhibited in other clinically relevant strains, such as Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae. In rich media and minimal media, the drug combination kills bacteria at a lower colistin concentration (1.25 μg/mL) compared to colistin alone (2.5 μg/mL). In minimal media, the combination is bactericidal with killing accelerated by up to 2 h compared to colistin alone. Importantly, no significant red blood hemolysis is evident for CDP-B11 alone or in combination with colistin. The characteristics of CDP-B11 presented here indicate that it can be used as a potential monotherapy or as combination therapy with colistin for the treatment of multidrug-resistant infections, including colistin-resistant infections.

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