Azithromycin resistance levels and mechanisms in Escherichia coli

Gomes, Cláudia; Ruiz-Roldán, Lidia; Mateu, Javier; Ochoa, Theresa J.; Ruiz, Joaquı́m

doi:10.1038/s41598-019-42423-3

Cited by 62 publications

(52 citation statements)

References 37 publications

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“…As no resistance breakpoint for azithromycin in E. coli has been adopted so far, we decided to sequence a few strains with MIC of 8–16 mg/L to investigate the presence of presumptive AMR determinants. The observed lack of acquired genes and specific mutations determining resistance for macrolides is congruent with previous reports on missing mechanisms of resistance in the vast majority of E. coli with azithromycin MIC ≤ 32 mg/L [ 29 ]. The same research revealed that MICs higher than 32 mg/L were associated with the presence of mph(A) .…”

Section: Discussionsupporting

confidence: 90%

Salmonella and Antimicrobial Resistance in Wild Rodents—True or False Threat?

et al. 2020

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Transmission of pathogenic and resistant bacteria from wildlife to the bacterial gene pool in nature affects the ecosystem. Hence, we studied intestine content of five wild rodent species: the yellow-necked wood mouse (Apodemus flavicollis, n = 121), striped field mouse (Apodemus agrarius, n = 75), common vole (Microtus arvalis, n = 37), bank vole (Myodes glareolus, n = 3), and house mouse (Mus musculus, n = 1) to assess their potential role as an antimicrobial resistance (AMR) and Salmonella vector. The methods adopted from official AMR monitoring of slaughtered animals were applied and supplemented with colistin resistance screening. Whole-genome sequencing of obtained bacteria elucidated their epidemiological relationships and zoonotic potential. The study revealed no indications of public health relevance of wild rodents from the sampled area in Salmonella spread and their limited role in AMR dissemination. Of 263 recovered E. coli, the vast majority was pan-susceptible, and as few as 5 E. coli showed any resistance. In four colistin-resistant strains neither the known mcr genes nor known mutations in pmr genes were found. One of these strains was tetracycline-resistant due to tet(B). High diversity of virulence factors (n = 43) noted in tested strains including ibeA, cdtB, air, eilA, astA, vat, pic reported in clinically relevant types of enteric E. coli indicate that rodents may be involved in the ecological cycle of these bacteria. Most of the strains represented unique sequence types and ST10805, ST10806, ST10810, ST10824 were revealed for the first time, showing genomic heterogeneity of the strains. The study broadened the knowledge on phylogenetic diversity and structure of the E. coli population in wild rodents.

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Section: Discussionsupporting

confidence: 90%

Salmonella and Antimicrobial Resistance in Wild Rodents—True or False Threat?

et al. 2020

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“…In contrast with the other macrolides, azithromycin has been shown to be more basic in character, which results in higher permeability across the outer membrane [7]. Thus, recently, a putative minimal inhibitory concentration (MIC) epidemiological cut-off value (ECOFF) of ≥32 mg/L was suggested for Escherichia coli using agar dilution according to the Clinical and Laboratory Standards Institute (CLSI), in order to discriminate wild-type from increased efflux or decreased permeability isolates, and to provide a decision rationale for alternative treatment of diarrheal infections [14].…”

Section: Introductionmentioning

confidence: 99%

Increased Azithromycin Susceptibility of Multidrug-Resistant Gram-Negative Bacteria on RPMI-1640 Agar Assessed by Disk Diffusion Testing

et al. 2020

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Increasing antibiotic resistances and a lack of new antibiotics render the treatment of Gram-negative bacterial infections increasingly difficult. Therefore, additional approaches are being investigated. Macrolides are not routinely used against Gram-negative bacteria due to lack of evidence of in vitro effectiveness. However, it has been shown that Pseudomonas spp. are susceptible to macrolides in liquid RPMI-1640 and clinical data suggest improvement in patients’ outcomes. So far, these findings have been hardly applicable to the clinical setting due to lack of routine low-complexity antimicrobial susceptibility testing (AST) for macrolides. We therefore optimized and compared broth microdilution and disk diffusion AST. Multidrug-resistant Gram-negative bacteria (Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Pseudomonas aeruginosa) were tested for azithromycin susceptibility by disk diffusion and broth microdilution in Mueller–Hinton and RPMI-1640 media. Azithromycin susceptibility of Enterobacteriaceae and a subgroup of P. aeruginosa increased significantly on RPMI-1640 agar compared to Mueller–Hinton agar. Further, a significant correlation (Kendall, τ, p) of zone diameters and minimal inhibitory concentrations (MICs) was found on RPMI-1640 agar for E. coli (−0.4279, 0.0051), E. cloacae (−0.3783, 0.0237) and P. aeruginosa (−0.6477, <0.0001). Performing routine disk diffusion AST on RPMI-1640 agar may lead to the identification of additional therapeutic possibilities for multidrug-resistant bacterial infections in the routine clinical diagnostic setting.

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“…In terms of azithromycin, the second-highest resistance pattern was observed among the isolates with a percentage of 86.25. Although azithromycin has been considered to be very effective against Enterobacteriaceae infections 30 , mutations in the outer membrane of Escherichia coli were reported to decrease the MICs of azithromycin 31 .…”

Section: Discussionmentioning

confidence: 99%

Isolation and Identification of Gram-Negative Bacteria from Oral Cancer Site Infections and Study of Their Antibiotic Resistance Pattern

Ashreen

Ahmed

Hasan

et al. 2020

Bangla. J. Microbiol.

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Cancer is one of the non-communicable lethal diseases which affects millions of people worldwide and is responsible for the majority of global deaths. Among the types of cancers occurring in humans, oral cancer has a higher incident rate which is significantly alarming. Oral cancer sites are associated with increased risk of metastasis, along with making the cancer site susceptible to infection by a vast number of opportunistic pathogens. Gram-negative opportunistic bacilli can dwell in these cancer ulcer sites since the patient becomes immune compressed due to radiotherapy and chemotherapy treatments, which prolong the infection. The present study was undertaken to find the most prevalent gram-negative bacilli in oral cavity cancer sites. Swab samples from 50 oral cancer patients were taken to check the presence of the opportunistic organisms. While the control group was set with people with no cancer, only 4 bacteria were isolated from 40 healthy volunteers. Among the isolates from both test group and control group, the most prevalent organism was Klebsiella species 37(45%), followed by Pseudomonas species 29 (34.5%) and Proteus species 8(9.5%). The least prevalent was Escherichia coli 5(6%). The isolates were all taken for antibiotic sensitivity testing (AST) against 15 antibiotics from 11 different groups used in hospitals. Results of the AST were as follows: 100% of the isolates from cancer patients were resistant to vancomycin, clindamycin, amoxicillin, penicillin G, and metronidazole. It was followed by azithromycin, where 86.25% of the isolates were resistant to it. The least resistance was seen against aminoglycoside antibiotic group, amikacin (6.25%), then gentamicin having a resistance percentage of 7.5. A substantial amount of qualitative data on medical history, clinical examination, and treatment, etc. was documented and presented in this study. Bangladesh J Microbiol, Volume 36 Number 2 December 2019, pp 85-90

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Azithromycin resistance levels and mechanisms in Escherichia coli

Cited by 62 publications

References 37 publications

Salmonella and Antimicrobial Resistance in Wild Rodents—True or False Threat?

Salmonella and Antimicrobial Resistance in Wild Rodents—True or False Threat?

Increased Azithromycin Susceptibility of Multidrug-Resistant Gram-Negative Bacteria on RPMI-1640 Agar Assessed by Disk Diffusion Testing

Isolation and Identification of Gram-Negative Bacteria from Oral Cancer Site Infections and Study of Their Antibiotic Resistance Pattern

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