β-lactam antibiotics are the greatest pharmaceutical development in modern medicine and are employed to treat numerous bacterial infections. Nonetheless, an alarming increase in antimicrobial resistance to β-lactam antibiotics has emerged primarily as a result of the extensive spread of β-lactamase enzymes such as extended-spectrum β-lactamases and carbapenemases, undermining the efficacy of available therapy, creating a global health problem through the rise in morbidity, mortality, and healthcare expenditure. Despite the development of β-lactamase inhibitors, the emergence of resistant β-lactamases necessitates the rapid discovery of new inhibitors or potentiators of existing antibiotics. Therefore, finding novel inhibitory compounds or a potentiator from alternative natural sources, such as medicinal plants, is imperative. Thus, this study aims to evaluate the potentiating effect of the crude extract of Melastoma malabathricum and other medicinal plants in combination with β-lactam antibiotics against resistant bacterial strains using in vitro as well as in silico study. The crude extract of Melastoma malabathricum was found to exhibit synergism against a CTX-M-producing E. coli when combined with cefotaxime, whose association of synergy with β-lactamase inhibition was confirmed using micro-iodometric assay and agar-based diffusion bioassay. It was further validated by molecular docking of the phytocompounds from the GC–MS study, in which 1,2-benzenedicarboxylic acid/NSC5348 exhibited the best binding energy with potential interactions with the active amino acid sites of the CTX-M. Thus, this compound was further chosen for a molecular dynamics simulation study with CTX-M-14, in which the complex was found to have good stability with consistent conformation throughout the simulation. Moreover, NSC5348 cleared drug-likeness filters. This finding highlights the β-lactamase inhibitory potential of Melastoma malabathricum, which may also act as a potentiator of β-lactams against the CTX-M producers. Thus, Melastoma malabathricum shows promise for use in combination therapy to combat drug resistance.

Microbial-mediated green synthesis of silver nanoparticles (AgNPs) represents an eco-friendly alternative to conventional chemical methods by utilising biological reducing and stabilising agents. In this study, gut bacteria isolated from sewage-exposed fish were used to synthesise AgNPs, and the resulting nanoparticles were evaluated for their antimicrobial and antioxidant activities. Bacterial biomass was used to reduce Ag+ ions from a 1 mM AgNO3 solution. Nanoparticle formation and characterisation were confirmed using UV–Visible spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD). A distinct color change from pale yellow to brown and a characteristic absorption peak at approximately 350–400 nm confirmed AgNP synthesis. TEM analysis revealed predominantly spherical nanoparticles ranging from 10 to 30 nm in size. The biosynthesised AgNPs exhibited antibacterial activity against both Gram-positive and Gram-negative bacteria including AmpC-producing Escherichia coli, producing inhibition zones in the range of 24–31 mm. The synthesised nanoparticles displayed strong dose-dependent antioxidant activity, in terms of DPPH and ABTS+ radical scavenging activity, with IC50 of 18 μg/mL and 39 μg/mL, respectively. These findings indicate the potential of sewage fish gut bacteria as a sustainable source for producing bioactive AgNPs with promising applications as an antibacterial agent.

Soil microorganisms play a significant role in mitigating hydric and edaphic stress, contributing significantly to sustainable agriculture. Hydric stress, caused by inadequate water availability, and edaphic stress, stemming from adverse soil conditions, both severely impact crop productivity. Soil microorganisms, including bacteria, fungi, and archaea, enhance plant resilience by improving soil structure, nutrient availability, and water retention. Microbial activities lead to the formation of soil aggregates, which enhance soil porosity and water infiltration, thus reducing hydric stress. Furthermore, these microorganisms facilitate the decomposition of organic matter, releasing essential nutrients like nitrogen, phosphorus, and potassium in bioavailable forms, thereby alleviating edaphic stress. Symbiotic relationships, such as mycorrhizal associations, extend the root surface area, enhancing water and nutrient uptake. Rhizobacteria directly contribute to soil fertility through processes like nitrogen fixation and phosphate solubilization. Certain soil microorganisms produce extracellular polysaccharides and other biofilms that help retain water and protect against soil erosion. These microbial exudates improve soil moisture content, buffering plants against drought conditions. Microbial inoculants, or biofertilizers, are increasingly used to harness these benefits, promoting sustainable agricultural practices by reducing the dependence on chemical fertilizers and pesticides. Understanding and leveraging the complex interactions between soil microorganisms and plants is crucial to developing resilient agricultural systems. Enhancing microbial diversity and activity through sustainable land management practices can lead to improved soil health, higher crop yields, and reduced environmental impact, paving the way for a more sustainable and resilient agricultural future.

The need for biofuel is growing with the tenacity of reducing greenhouse gaseous emission leading to deviations in climate and global warming effect. For worldwide constancy, commercial affluence, and quality of life a clean energy sources like microbial fuels could be an alternative substitute to that of fossil fuels. These biofuels are safe, renewable and reduce green-house gas emissions. Microorganisms in such platform is useful as they do not involve land for cultivation, do not strive for food production and these can be cultured easily under laboratory conditions. Altogether, plants in nature hold endophytes and it is essential to comprehend their biodiversity and role in the host plants. These endophytic microbes' mainly fungal endophytes are considered, to be a treasure of structurally and biologically exceptional natural products. Most of these compounds are those formed by their corresponding host plants as well and henceforth for the construction of equivalent compounds, endophytes from the host plants are valuable. Endophytic fungi possess a suitable lipid matrix at high concentrations and volatile organic compounds containing resemblance with conventional diesel fuel that make them promising sources for next generation biofuels.

Extended-spectrum β-lactamases (ESBL) producing enterobacteriales are a major global health concern since they often result in the ineffectiveness of empirical antibiotic therapy with β-lactams. This study aims to identify potential medicinal plants that can inhibit β-lactamase and subsequently enhance the activity of the β-lactams against resistant bacterial strains. A synergistic study of Dichrocephala integrifolia extract exhibited good synergistic activity against a CTX-M-producing organism, which was confirmed using an agar-based diffusion bioassay method. Further validation was done by Molecular docking in which, the phytocompound Propanamide, N-[4-(4-chlorophenyl)-2-thiazolyl]-3-(1-pyrrolidinyl)-/NSC339591, obtained from the GC-MS study showed a good binding affinity with favourable hydrogen bond interactions with the active sites of CTX-M-14. This phytocompound was further selected for a Molecular Dynamic Simulation (MD) study with CTX-M-14, where the complex exhibited good stability and maintained a consistent conformation throughout the simulation. NSC339591 cleared the drug-likeness filters.

Background: Tyrosinase is an enzyme involved in the production of L-DOPA. To look for novel tyrosinase inhibitors, we investigated the non-protein fraction from the sericin extract of the silk cocoon shell of Antheraea proylei J. for its ability to inhibit tyrosinase. Materials and Methods: The non-protein fraction was subjected to GC-MS studies. The compounds identified from the GC-MS study were screened in silico for their ability to bind to tyrosinase enzyme. In vitro tyrosinase inhibitory assay of the non-protein extract was also studied. Results and Discussion: Our results showed that the component, 1,3-bis(cinnamoyloxymethyl)adamantine showed stable binding with the tyrosinase enzyme. Molecular dynamics simulation of the complex of 1,3-bis(cinnamoyloxymethyl)adamantine and tyrosinase showed steady root mean square deviation values, Radius of gyration, root mean square fluctuation and solvent accessible surface area. Hydrogen bonding and van der Wals interaction were present between the ligand and the enzyme. In vitro tyrosinase assay showed that our extract had tyrosinase inhibitory effects. Conclusion: The non-protein fraction from the sericin extract of Antheraea proylei J. can be further studied for their feasibility as a commercially available tyrosinase inhibitor.

The present study aims to identify potential medicinal plant-based extended-spectrum β-lactamase (ESBL) inhibitors from Andrographis paniculata using both in silico and in vitro approaches. The ESBLs were obtained from the protein data bank. The structures of phytoconstituents were obtained from the PubChem database. The compounds were docked against different ESBLs (targeted proteins) using AutodockTools followed by molecular dynamics simulation. In silico results were further validated using in vitro testing through the disc diffusion method. The molecular docking revealed that most of the phytoconstituents have a good binding affinity. The binding energy and in vitro study of the phytoconstituents of Andrographis paniculata were compared with the standard inhibitor for ESBL i.e. clavulanic acid .14- Acetylandrographolide (AAD) showed good binding with the ESBL proteins, having the best values reported in the docking with OXA-10. Simulation of the complex of AAD and OXA-10 showed that the complex was relatively steady as evidenced by the lack of sudden fluctuations in the values of root mean square deviations, the radius of gyration and solvent-accessible surface area. Further confirmation of the in silico approach was done by an in vitro study against ESBL-producing organisms which showed inhibitory results. From this study, we can conclude that A.paniculata may have the potential to inhibit ESBLs and may be considered for treating bacterial infections.

A wide range of intrinsic Acinetobacter-derived cephalosporinases (ADC) along with other carbapenemases has now been detected in Acinetobacter baumannii leaving clinicians with few treatment options. The present study reports the spread of ADC-30 co-producing KPC-2 along with other β-lactamases among carbapenem resistant A. baumannii strains obtained from ICU patients in two Indian hospitals. Primer extension analysis revealed higher transcript level of the ADC gene when induced with cefoxitin at 8 μg/ml (170 fold), ceftriaxone at 8 μg/ml (136 fold), ceftazidime at 4 μg/ml (65 fold), cefepime at 8 μg/ml (77 fold) and aztreonam at 8 μg/ml (21 fold) when compared with the basal level without antibiotic pressure. Slight increase in expression of blaADC-30 when induced with imipenem and meropenem at 0.25 μg/ml (3 and 6 fold) was observed and may help in conferring resistance to carbapenem. MLST analysis revealed the circulation of A. baumannii sequence types ST188, ST386, ST583 and ST390 in these hospitals.

Recently, different nanocrystals have been reported to be the alternative, optimistic, and novel antimicrobial agent against the many antibiotic‐resistant bacteria. Here, ligand‐free CdS and Ag‐doped CdS (Ag/CdS) nanocrystals have been synthesized by chemical methods for the study of the antimicrobial activity on Escherichia coli and Staphylococcus aureus by Kirby–Bauer diffusion method to see the effect against Gram‐positive and Gram‐negative bacteria. These prepared nanocrystals have been characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD). TEM and SEM images confirm the spherical morphology of both the sample and the respective XRD patterns indicate polycrystalline nature having a cubic zinc blende structure. Antibacterial activities have been tested with CdS and Ag/CdS, considering concentrations ranging from 10 to 200 μg/ml. After 24 h of incubation, the zone of inhibition (ZOI) is measured for each concentration, which shows that both the nanocrystals are ineffective against E. coli but much effective against S. aureus at this low concentration range. Furthermore, Ag/CdS nanocrystals have been found to show much more ZOI than CdS. Differences in the antibacterial activity can be due to the presence of different cell wall in E. coli and S. aureus.

OBJECTIVES:This study investigated the occurrence of extended-spectrum β-lactamase (ESBL) genes coexisting with carbapenemase, AmpC and aminoglycoside resistance gene in uropathogens in India.METHODS:Antimicrobial susceptibility testing was performed by disk diffusion. Antimicrobial resistance genes were detected by multiplex PCR.RESULTS:Of 1516 consecutive urine samples, 454 (29.9%) showed significant bacteriuria with a single micro-organism, predominantly Escherichia coli (n=343), followed by Klebsiella pneumoniae (n=92), Pseudomonas aeruginosa (n=10) and Proteus mirabilis (n=9). Among the uropathogens, 61 ESBL-producers were identified containing blaCTX-M-15 (n=32), blaCTX-M-15+blaOXA-2 (n=15), blaCTX-M-15+blaOXA-2+blaTEM-1 (n=6), blaOXA-2 (n=5), blaOXA-2+blaSHV-76 (n=1), blaTEM-1+blaSHV-76 (n=1) and blaTEM-1 (n=1). All ESBL genes were located on horizontally transferable plasmids of incompatibility types HI1, I1, FIA+FIB, FIA and Y. Among the 61 ESBL-producers, 59 harboured carbapenemase genes, including blaNDM-5 (n=48), blaNDM-5+blaOXA-48 (n=5), blaNDM-5+blaIMP (n=5) and blaNDM-5+blaIMP+blaVIM (n=1). ESBL-producing uropathogens also harboured 16S rRNA methylase genes, including rmtB (n=9), rmtA (n=4), rmtC (n=1) and armA (n=1). ESBL-positive isolates also contained AmpC genes, including blaCIT (n=8) and blaDHA-1 (n=1). Imipenem and gentamicin had the lowest resistance rates against the uropathogens.CONCLUSION:This is the first report showing the high prevalence of carbapenemases in ESBL-positive isolates in this area. Regular surveillance for such resistance mechanisms will be useful for health personnel to treat infections by these multidrug-resistant pathogens.

Extended-spectrum β-lactamase (ESBL) producing bacteria acts as a serious threat, and its co-existence with other antibiotic resistant gene makes the clinical scenario worse nowadays. Therefore in this study, we investigated the occurrence of ESBL genes coexisting with carbapenem, AmpC and aminoglycoside resistance gene in uropathogens. Out of 1516 urine samples, 454 showed significant bacteriuria with a prevalence rate of 29.94 %. Escherichia coli (n=340) were found to be the most predominant uropathogen followed by Klebsiella pneumoniae (n=92), Pseudomonas aeruginosa (n=10) and Proteus mirabilis (n=9). Among the total uropathogens, sixty-three ESBL-producers were identified which included bla CTX-M-15 (n=32), followed by bla CTX-M-15 + bla OXA-2 (n=15), bla CTX-M-15 + bla OXA-2 + bla TEM (n=6), bla OXA-2 (n=5), bla OXA-2 + bla SHV-76 (n=1), bla TEM+SHV-76 (n= 1) and bla TEM (n=1). All ESBL genes were found on plasmid incompatibility types: HI1, I1, FIA+FIB, FIA and Y and were horizontally transferable. Among 63 ESBL-producers, 59 isolates harboured carbapenem-resistant genes which included bla NDM-5 (n=48), bla NDM-5 + bla OXA-48 (n=5), bla NDM-5 + bla IMP (n=5) and bla NDM-5 + bla IMP + bla VIM (n=1). The ESBL producing uropathogens also harbored 16S rRNA methylase genes which included rmtB (n=9), rmtA (n=4), rmtC (n=1) and ArmA (n=1) followed by AmpC genes which includes CIT (n=8) and DHA-1 (n=1) genes. Imipenem and gentamicin were found to be more effective. We speculating, this is the first report showing the prevalence of multidrug-resistant uropathogens in this area demanding regular surveillance for such resistance mechanisms which will be useful for health personnel to treat ESBL infection and its co-existence with another antibiotic resistance gene.

Objectives: Plasmids of different replicon types are believed to be associated with the carriage and transmission of antimicrobial resistance genes. The present study was undertaken to examine the association of bla(CIT) with particular plasmid types and to identify Escherichia coli strains involve in the maintenance of this resistance determinant in the plasmid. Methods: Phenotypic screening of AmpC beta-lactamases was performed by the modified three-dimensional extract method, followed by antimicrobial susceptibility testing and determination of minimum inhibitory concentrations (MICs). Genotyping screening of beta-lactamase genes was performed by PCR assay, followed by sequencing. Transferability of the bla(CMY) gene was performed by transformation and conjugation experiments. Plasmid incompatibility typing and DNA fingerprinting by enterobacterial repetitive intergenic consensus (ERIC)-PCR were performed. Results: Among 203 E. coli obtained from different clinical specimens (pus, urine, stool and sputum), 37 were detected as harbouring the bla(CIT) gene and sequencing of this gene showed nucleotide sequence similarity with the bla(CMY-42) variant. This study revealed IncI1-type plasmids as carriers of bla(CMY-42) and its propagation within E. coli ST5377, ST361 and ST672. According to the stability results, the bla(CMY-42)-encoding plasmid can be maintained in E. coli strains for a longer duration without any antimicrobial pressure. Conclusions: These finding document bla(CMY-42) on IncI1-type plasmids, which are considered to be the main vehicles for the spread of bla(CMY-42) in this hospital setting. Thus, a proper strategy should be developed to curb the expansion of IncI1-type plasmids in the hospital and community environment. (C) 2018 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.

Two Klebsiella strains isolated from urine samples were positive for blaAmpC by PCR and showed sequence similarity with CMH-1 (98.6%) after sequencing. It also shares 82% similarity with ACT-1, 85% with MIR-1 and 81% with the chromosomal AmpC gene of Enterobacter cloacae. This gene was associated with the plasmid of IncK type. It has an open reading frame of 381 amino acid with four amino acid substitutions at position D144A, C189R, Q192E, and A195T as compared to CMH-1. When expressed in E.coli DH5α and E.coli strain B, this β-lactamase conferred resistance to cefotaxime, ceftriaxone and ceftazidime. In addition, both in vitro and in silico analysis revealed that this cephalosporinase was inhibited by cefepime and carbapenem group of drugs. Therefore, this new plasmid-encoded AmpC type β-lactamase gene was designated as CMH-2.

The blaOXA-23 group was considered as the first group of OXA-type β-lactamases conferring carbapenem resistance and has been reported worldwide in Acinetobacter baumannii, however their presence in Escherichia coli is very rare and unique. This study describes an unusual occurrence of blaOXA-23 in 14 clinical isolates of E. coli obtained from intensive care unit patients admitted to a tertiary referral hospital in India. The blaOXA-23 gene was found located within a self-conjugative plasmid of IncFrepB and IncK incompatibility types and simultaneously carrying blaCTX-M-15, blaVEB-1, blaPER-1 and/or blaNDM-1. The copy number of blaOXA-23 within the IncK-type plasmid was inversely proportional to increasing concentrations of imipenem, whereas in the case of the IncFrepB-type the result was variable; and increased copy number of the IncK-type plasmid was observed with increasing concentrations of meropenem. Plasmids encoding blaOXA-23 could be successfully eliminated after single treatment and were found to be not highly stable, as complete loss of plasmids was observed within 5-10 days. This study emphasises that carbapenem stress invariably altered the copy number of two different Inc type plasmids encoding the blaOXA-23 resistance gene and also highlights a potential threat of clonal expansion of this class D carbapenemase through a heterologous host in this country, which is in second incidence globally.

The current study reports dissemination of highly stable bla OXA-10 family of beta lactamases among diverse group of nosocomial isolates of Gram-negative bacilli within a tertiary referral hospital of the northern part of India.

Bacteria of the genera Klebsiella and Raoultella, which are present in foods and the natural environment, are associated with health hazards in humans. In the present study, two types of strips-based methods were developed to detect these bacteria simply and quickly. One method used lateral-flow test strips (LFTS) in combination with anti-Klebsiella antibodies labeled with palladium nanoparticles that bind to target bacteria, allowing their visualization. In the other, the antibodies were immobilized on nitrocellulose membranes, and urease activity was measured using an ion sensitive field effect transistor pH sensor. Testing of a combination of these two methods on 72 cultured strains successfully identified all 25 strains of Klebsiella pneumoniae, Klebsiella oxytoca and Raoultella ornithinolytica. This approach also accurately identified 76 of 77 (99%) strains isolated from meats and pastries. When combined with preculture, this method was accurate in identifying 19 of 26 (73%) target bacteria in food. These results suggest that the novel combination of strip-based assays may be effective for the on-site monitoring of food production plants, and thereby enhance food safety.

BACKGROUND:New-Delhi metallo-β-lactamase-7 with higher hydrolytic activity than its ancestor NDM-1 is emerging across the globe including India. In this study, we have investigated the genetic context of blaNDM-7 and alteration in plasmid copy number under concentration gradient carbapenem stress.MATERIALS AND METHODS:Six blaNDM-7 producing Escherichia coli isolates were obtained from Silchar Medical College and Hospital and the co-existence of other β-lactamases and transferability of this resistant determinant was determined by transformation and conjugation assay followed by typing of the plasmid by PBRT method. Genetic context and plasmid stability of blaNDM-7 was also determined. The change in copy number of transconjugable plasmid carrying blaNDM-7 under exposure of different carbapenem antibiotics was determined by quantitative Real Time PCR.RESULTS:All the six isolates carrying blaNDM-7 were conjugatively transferable through an IncX3-type plasmid and were also found to co-harbor blaCTX-M-15. Genetic analysis of blaNDM-7 showed an association of ISAba125, IS5 and a truncated portion of ISAba125 in the upstream region and bleMBL gene in the downstream region of blaNDM-7. Complete loss of the plasmids carrying blaNDM-7 was observed between 85th to 90th serial passages when antibiotic pressure was withdrawn. After analyzing the relative copy number it was observed that the copy number of the blaNDM-7 encoding plasmid was highly affected by the concentration of ertapenem.CONCLUSION:The present study has first demonstrated presence of IncX3-type plasmid encoding blaNDM-7 within nosocomial isolates of E. coli. Measures must be taken to prevent or atleast slowdown the emergence of this resistance determinant in this country.

Background & objectives: Pseudomonas aeruginosa possessing chromosomally inducible blaPDCalong with other intrinsic mechanism causes infection with high mortality rate. It is difficult to detect inducible AmpC enzymes in this organism and is usually overlooked by routine testing that may lead to therapeutic failure. Therefore, three different inducers were evaluated in the present study to assess their ability of induction of blaPDCin P. aeruginosa. Methods: A total of 189 consecutive Pseudomonas isolates recovered from different clinical specimens (November 2011-April 2013) were selected for the study. Isolates were screened with cefoxitin for AmpC β-lactamases and confirmed by modified three-dimensional extract test (M3DET). Inductions were checked using three inducers, namely, clavulanic acid, cefoxitin and imipenem along with ceftazidime. Molecular screening of AmpC β-lactamase genes was performed by PCR assay. Antimicrobial susceptibility and minimum inhibitory concentrations (MICs) were determined, and repetitive extragenic palindromic-PCR of all blaPDCharbouring isolates was performed. Results: Inducible phenotype was observed in 42 (24.3%) of 97 (56%) isolates confirmed by M3DET. Among these, 22 isolates harboured chromosomal blaPDCgene, and cocarriage of both chromosomal and plasmid-mediated blaAmpC genes was observed in seven isolates. Cefoxitin-ceftazidime-based test gave good sensitivity and specificity for detecting inducible AmpC enzymes. Isolates harbouring blaPDCshowed high MIC against all tested cephalosporins and monobactam. DNA fingerprinting of these isolates showed 22 different clones of P. aeruginosa. Interpretation & conclusions: P. aeruginosa harbouring inducible (chromosomal) and plasmid-mediated AmpC β-lactamase is a matter of concern as it may limit therapeutic option. Using cefoxitin-ceftazidime-based test is simple and may be used for detecting inducible AmpC β-lactamase amongst P. aeruginosa.

Treatment alternatives for DHA-1 harboring strains are challenging as it confers resistance to broad spectrum cephalosporins and may further limit treatment option when expressed at higher levels. Therefore, this study was designed to know the prevalence of DHA genes and analyse the transcription level of DHA-1 against different β-lactam stress.

OBJECTIVES:Quinolone antimicrobials are frequently misused due to self-medication and suboptimal dose administration, leading to the development of resistance as well as treatment failure. The present study aimed to characterise plasmid-mediated quinolone resistance (PMQR) determinants and their genetic selection in the presence of quinolone stress within members of the Enterobacteriaceae. METHODS:A total of 209 non-duplicate Enterobacteriaceae isolates were collected from hospital and community health centres over the period July 2013-June 2014. Molecular characterisation of phenotypically screened quinolone-resistant isolates was done by multiplex PCR. Plasmids bearing the qnr and aac(6')-Ib-cr genes were transformed into Escherichia coli DH5α and were selected on Muller-Hinton agar plates containing 0.25μg/mL and 0.5μg/mL ciprofloxacin, norfloxacin, ofloxacin, levofloxacin and moxifloxacin. Conjugation experiments were performed to determine whether the aac(6')-Ib-cr- and qnr-carrying plasmids were self-transferable. RESULTS:The transformation assay revealed that transformants carrying qnrA could be selected in media containing norfloxacin, ciprofloxacin and levofloxacin, whereas qnrB and aac(6')-Ib-cr were selected on media containing norfloxacin and ciprofloxacin. Transformed qnrD could be selected in media containing norfloxacin and ofloxacin, and qnrS was selected only in the presence of levofloxacin. CONCLUSIONS:The presence of qnr genes has been associated with an increase in quinolone minimum inhibitory concentrations (MICs) and therefore leads to treatment failure when quinolones are used as selective therapeutic drugs. Since PMQR determinants have a high prevalence, effective measures should be taken and surveillance should be performed in order to avoid treatment failures using this group of antimicrobials.