Multiresistant Isolates Research Articles

Characterization of Salmonella enterica serovars recovered from meat products legally and illegally imported into the EU reveals the presence of multiresistant and AmpC-producing isolates

BackgroundFood products of animal origin brought into the EU from third countries, both legally and illegally, can harbor foodborne pathogens such as Salmonella enterica. In this study, we examined five S. enterica isolates recovered either from legally imported chicken meat (n = 3) or from meat products confiscated from air travel passengers arriving in Germany (n = 2). The isolates were serotyped and further characterized by antimicrobial susceptibility testing, PCR-detection and sequencing of genes associated with antimicrobial resistances, and macrorestriction analysis. Transferability of resistance to third-generation cephalosporins was assessed by conjugation experiments and the plasmids tested for their incompatibility groups.ResultsThe three isolates from legal imports were identified as S. Heidelberg or as non-flagellated. All three isolates were identified as AmpC producers carrying blaCMY-2 and as non-susceptible to ciprofloxacin. They were additionally resistant to tetracycline and sulfamethoxazole. The blaCMY-2-carrying plasmids were transferable by conjugation and belonged to incompatibility groups IncI1 or IncA/C. The two isolates from illegally imported meat belonged to the serovars Infantis or Weltevreden. The former was phenotypically resistant to five classes of antimicrobial agents while the S. Weltevreden isolate was fully susceptible to all agents tested.ConclusionThe results of this study demonstrate that meat products imported from third countries, both legally and illegally, can harbor multiresistant Salmonella enterica. Consequently, these imports could constitute a source for the dissemination of antimicrobial resistant isolates, including those resistant to third-generation cephalosporins and fluoroquinolones.

Bactericidal synergism between antibiotics and phage endolysin Cpl-711 to kill multidrug-resistant pneumococcus.

Aim:To test the synergistic effect of Cpl-711 endolysin and antibiotics for antipneumococcal activity.Materials & methods:A combination of Cpl-711 and different antibiotics (amoxicillin, cefotaxime, levofloxacin and vancomycin) was tested in a checkerboard assay against several multidrug-resistant Streptococcus pneumoniae strains. Mouse and zebrafish models of pneumococcal sepsis were used to confirm the in vitro data.Results:The activity of Cpl-711 combined with amoxicillin or cefotaxime was synergistic in the bactericidal effect against a serotype 23F multiresistant clinical isolate of S. pneumoniae. Synergy between Cpl-711 and cefotaxime was validated using both mouse and zebrafish models.Conclusion:Combination of Cpl-711 and cefotaxime may help in the treatment of diseases caused by multiresistant pneumococcal strains.

An amphipathic cyclic tetrapeptide scaffold containing halogenated β2,2‐amino acids with activity against multiresistant bacteria

The present study describes the synthesis and biological studies of a small series of head-to-tail cyclic tetrapeptides of the general structure c(Lys-β2,2 -Xaa-Lys) containing one lipophilic β2,2 -amino acid and Lys, Gly, Ala, or Phe as the Xaa residue in the sequence. The peptides were investigated for antimicrobial activity against gram-positive and gram-negative reference strains and 30 multiresistant clinical isolates including strains with extended spectrum β-lactamase-carbapenemase (ESBL-CARBA) production. Toxicity was determined against human red blood cells. The most potent peptides showed high activity against the gram-positive clinical isolates with minimum inhibitory concentrations of 4-8μg/mL and low haemolytic activity. The combination of high antimicrobial activity and low toxicity shows that these cyclic tetrapeptides containing lipophilic β2,2 -amino acids form a valuable scaffold for designing novel antimicrobial agents.

Escherichia coli used as a biomarker of antimicrobial resistance in pig farms of Southern Brazil

The objective of this study was to verify the presence of antimicrobial resistant strains of Escherichia coli in pig farms and to use it as a biomarker to evaluate phenotypic and genotypic profiles of antimicrobial susceptibility, as well as the presence of Extended Spectrum Beta-lactamases (ESBLs) and fluoroquinolone resistance genes. Several samples (n = 306) collected from swine farms (n = 100) of Southern Brazil were used for E. coli isolation: 103 of swine feces, 105 of water, and 98 of soil. E. coli isolates were submitted to the disk-diffusion test to verify their antimicrobial susceptibility, to disk-approximation test to detect ESBL-producers, and to PCR analysis to search for ESBLs genes (blaCTY-M2, blaSHV-1, blaTEM-1, blaCTX-M2, blaOXA-1, blaPSE-1) and quinolone resistance genes (qnrA, qnrB and qnrS). The percentage of E. coli isolates found in feces, water and soil samples was 66.02%, 30.48% and 35.71%, respectively. The highest percentages of resistance were obtained for sulfamethoxazole associated with trimethoprim (63.70%), colistin (45.19%) and enrofloxacin (39.26%). Regarding the levels of multidrug resistance, 37.04% of the isolates were resistant to three or more classes of antimicrobials. The most common profile (16%) of multirresistance was GEM-SUT-ENO-COL. The index of multiple resistance to antimicrobials (IRMA) was above 0.2 in 78% of the multiresistant isolates. Out of 135 E. coli isolates, 7.41% was ESBL-producers, of which 50% showed the blaCMY-M2 gene, 40% the blaTEM-1 and 70% the qnrS gene. Of non-ESBL-producing strains resistant to enrofloxacin, 13.04% were positives for qnrS gene. These results demonstrated the presence of fecal contamination in the environment, in addition to high resistance indexes for several antimicrobials, including beta-lactams and fluoroquinolones, which was confirmed by the genetic detection of ESBLs and qnr genes.

Antimicrobial Resistance of Uropathogenic Escherichia coli from Elderly Patients at a General Hospital, Argentina

Background:Urinary Tract Infection (UTI) is a common cause of morbidity and mortality in older adults.Objective:To investigate antimicrobial resistance of uropathogenicEscherichia colifrom elderly patients in a General Hospital, Argentina.Method:During the period July 2011-July 2015, patients over 70 years old with urinary tract infections, without urinary catheters and with no antimicrobial therapy the previous week before sampling, were included. Phenotypic characterization was carried out.In vitroqualitative and quantitative antimicrobial resistances were investigated. Antimicrobials assayed: ampicillin, amoxicillin-clavulanate, cefazolin, cefuroxime, cefoxitin, cefotaxime, ceftazidime, cefepime, imipenem, ertapenem, gentamicin, nalidixic acid, ciprofloxacin, trimethoprim-sulfamethoxazole (TMS) and nitrofurantoin. Patients’ medical records were produced, and risk factors were analyzed by multivariate analysis.Results:768 bacterial isolates were identified asE. coli. Resistances to ampicillin (80.5%), nalidixic acid (61.7%), ciprofloxacin (42.8%), TMS (37.6%), amoxicillin-clavulanate (28.6%), cefazolin (21.6%), cefuroxime (20.7%), gentamicin (13.8%), cefotaxime (9.7%), ceftazidime (9.7%), cefepime (8.4%), cefoxitin (3.1%) and nitrofurantoin (2.3%) were observed. Resistance to carbapenems was not expressed. Production of extended spectrum β-lactamases was detected (7.6%) in community acquired (96%) and healthcare associated (4%) isolates. The independent risk factors for urinary infections produced by multi-resistantE. coliwere: diabetes mellitus, recurrent infections, hospitalization during the last year and exposure to β-lactams in the last 3 months.Conclusion:A high prevalence of resistance to β-lactams and to other antimicrobials was observed. Detection of antimicrobial multi-resistant isolates highlights the need of antimicrobial resistance surveillance in elderly patients with urinary tract infections.

Asymptomatic carriage of antibiotic-resistant Gram-positive cocci among different background populations in East Timor, Southeast Asia.

Dissemination of pathogenic multiresistant bacteria is of public health concern. Reliable data can be difficult to obtain, especially in developing countries. This work aimed to characterize the skin and oropharyngeal microbiota, as well as their antimicrobial resistance profiles, of East-Timor populations to identify potentially pathogenic Gram-positive cocci. In order to assess the prevalence of pathogenic bacteria in East-Timor, the oropharyngeal and skin microbiota of 74 individuals was characterized. Gram-positive cocci were evaluated and their antimicrobial resistance profiles were determined. A total of 228 oropharyngeal and 278 skin samples were obtained. The population consisted of 36.5% of asymptomatic carriers of Gram-positive cocci. Kocuria rosea (n = 7, 19.4%), Staphylococcus spp. (n = 6, 16.7%), and Micrococcus luteus (n = 6, 16.7%) were isolated, among others. Antimicrobial resistance levels ranged between 0% and 36.1%, and a multiresistance profile was observed in one third of the isolates. Gram-positive cocci colonization was associated with age group. Prevalence of multiresistant isolates was higher in males who were sampled at the refugee camp. Results show that the prevalence of antimicrobial resistance on East Timor may be underestimated. This study represents the first step toward the full characterization of potential pathogenic Gram-positive cocci present in the populations from East Timor.

Achieving high antimicrobial activity: Composite alginate hydrogel beads releasing activated charcoal with an immobilized active agent

New composites based on Ca-alginate hydrogels were produced that release activated charcoal (AC) particles with adsorbed povidone iodine (PVP-I) as a model antimicrobial substance in a physiological-like environment. Composite beads with different alginate (0.5–1.5%w/w) and AC (1–20%w/w) concentrations were analyzed by FE-SEM and characterized regarding textural parameters, swelling, and AC release kinetics. PVP-I was easily adsorbed onto AC particles within the optimized beads (0.5%w/w alginate, 20%w/w AC) as indicated by UV–vis spectroscopy, EDX and FT-IR analyses. The obtained beads have shown strong bactericidal effects against two standard bacterial strains (Staphylococcus aureus and Pseudomonas aeruginosa) and clinical multi-resistant wound isolates (MRSA, Escherichia coli, Pseudomonas aeruginosa, Еnterococcus faecalis and Proteus mirabilis) and, at the same time, exhibited negligible PVP-I desorption in physiological saline solution. Thus, the obtained composites could provide utilization of potent antiseptics such as iodine, in wound dressings, without the concern of systemic absorption.

Frequency and antimicrobial susceptibility of Staphylococcus pseudintermedius in dogs with otitis externa

ABSTRACT: Infections by Staphyloccocus pseudintermedius in the skin of dogs have been object of studies, since such microorganisms often present multiple resistance to antibiotics. This study aimed to identify and evaluate the antimicrobial susceptibility of Staphylococcus pseudintermedius (SP) strains isolated from dogs with otitis. Swabs from both ears of 52 dogs with otitis (n=104) were included. Bacteria were cultured using Muller-Hinton agar (supplemented with 5% equine blood and incubated at 37°C for 24 to 48 hours. All colonies underwent biochemical evaluation for identification of staphylococci. The identity of colonies as SP was confirmed by polymerase chain reaction. The antimicrobial susceptibility of SP strains was evaluated by disk diffusion. The presence of the gene mecA was evaluated in all SP isolates by PCR. Forty-four SP strains were isolated from swabs of 31 dogs (31/52, 59.6%). Seventy-five percent of the strains were susceptible to cephalexin and 93.2% to amoxicillin plus clavulanic acid. Less than 23% of the strains were susceptible to penicillin. For non-beta-lactam antimicrobials, 63.6% of the strains showed resistance to sulfamethoxazole-trimethoprim, 61.4% to tetracycline, and 38, 64% to enrofloxacin. Aminoglycoside resistance rate was 27.3% for gentamicin. Resistance to oxacillin in vitro was detected in 13 of the 44 strains (29, 55%). A total of 12 strains (27.3%) were positive for mecA gene and five of these 12 strains were susceptible to in vitro oxacillin. Twenty-six (59, 1%) strains were resistant to three or more classes of antimicrobials, and classified as multi resistant. Our results showed high frequency of SP and multi resistant isolates to antimicrobials commonly used in veterinary.

Monitoring of multiresistant community-associated MRSA strains from patients with pathological processes of different localization

The therapy of infections, caused by methicillin-resistant Staphylococcus aureus (MRSA) with multiple resistance to antibiotics remains one of the most acute problems all over the world. It is all the more complicated since a priori the MSRA strains are not sensitive to the group of β-lactam antibiotics and multiresistant isolates are resistant to other groups of antimicrobial preparations, including antibiotics of choice (rifampicin, vancomycin, fusidic acid, co-trimoxazole and linezolid). From the samples of biomaterials of patients with pathological processes of different localization, we isolated 335 strains of bacteria, which were identified as Staphylococcus aureus, 169 (50.4%) of which were methicillin-resistant variants: 57.5% cultures were isolated from the nasal discharge; 50.7% – from faeces at intestinal dysbioses; by 40.0% – from conjunctival discharge, pharyngeal swab, outer ear swab and sputum; 33.3% – from urine samples. Antibiotic susceptibility of the isolated cultures was estimated by the disc-diffusion method and the method of serial dilution. The MRSA strains appeared to be most resistant to gentamycin, erythromycin (by 59.5% of cultures) and ciprofloxacin (53.3% of isolates), most sensitive – to vancomycin, co-trimoxazole and fusidic acid. The frequency of isolation of the cultures that are resistant to antibiotics did not exceed 4.1%. Rifampicin suppressed the growth of 75.8% and linezolid – of 100.0% of strains. Depending on the kind of biomaterial taken, MRSA strains, isolated from the nasal cavity, outer ear, urine samples, samples of sputum and faeces at intestinal dysbioses proved to be most resistant to the tested antimicrobial preparations. Rifampicin- and vancomycin-resistant strains of methicillin-resistant staphylococci made up 21.3% of the total number of the detected MRSA. They were most often isolated from the clinical samples taken from the nasal cavity and faeces. When determining minimal inhibitory concentration (MIC) of rifampicin and vancomycin, which are antibiotics of choice for treatment of infections caused by multiresistant MRSA, it was found that for 55.5% of the MRSA strains isolated from faeces, MIC of rifampicin coincided with the threshold value for this antibiotic and for 44.5%, it exceeded the threshold value by 2 times (4 µg/ml). 22.2% of them were characterized by the critical value of susceptibility to vancomycin (MIC ≥ 2 µg/ml). From rifampicin- and vancomycin-resistant MRSA stains, isolated from the nasal cavity, MIC of rifampicin coincided with the threshold value for this antibiotic for 66.7% of cultures, and exceeded it at least by 2 times for 33.3%. 11.1% of them were characterized by the critical level of susceptibility to vancomycin (MIC ≥ 2 µg/ml) and by 3.7% of strains exceeded MIC by 2 and 4 times respectively (4 and 8 µg/ml).

A novel tool against multiresistant bacterial pathogens: lipopeptide modification of the natural antimicrobial peptide ranalexin for enhanced antimicrobial activity and improved pharmacokinetics

As evolutionarily optimised defence compounds, antimicrobial peptides (AMPs) represent a powerful tool against bacterial infections. Ranalexin, an AMP found in the skin of the American bullfrog (Rana catesbeiana), is primarily active against Gram-positive bacteria, with minimum inhibitory concentrations (MICs) of 8-16 mg/L, but shows weaker activity against Gram-negative bacteria (MICs > 64 mg/L). By substitution of six N-terminal amino acids by saturated fatty acids [decanoic acid (C10:0) to myristic acid (C14:0)], lipopeptide derivatives with enhanced antimicrobial activity were developed. The antimicrobial capacity of the peptides was tested against different bacterial strains, including multiresistant clinical isolates. C13C3lexin, the most potent derivative, showed MICs of 2-8 mg/L against Gram-positive bacteria and 2-16 mg/L against Gram-negative bacteria. In time-kill studies, it was clearly shown that ranalexin and the lipopeptide C13C3lexin function as concentration-dependent, fast-acting substances against different bacteria. Cell viability assays revealed that cytotoxicity towards human cells increases with the chain length of the attached fatty acid (IC50, 12.74-108.10 µg/mL). Furthermore, using positron emission tomography (PET) imaging, pharmacokinetic studies of 68Ga-labelled ranalexin and its derivatives were performed for the first time. Here it was demonstrated that ranalexin is rapidly cleared via the kidneys within 1 h post-injection. In contrast, the lipopeptide showed greatly extended circulation in the bloodstream and a shift from renal to hepatic accumulation characteristics. Therefore, the more favourable pharmacokinetics and enhanced antimicrobial activity clearly demonstrate the potential of the lipopeptide AMPs as novel ammunition against emerging multiresistant bacterial pathogens.

Antimicrobial activity of essential oils extracted from leaves of native Moroccan plants against clinical bacterial isolates

Introduction: Medicinal plants are plentiful of bioactive molecules effective against multi-resistance bacteria. The aims of this study were to assess the in vitro antimicrobial activities of essential oils extracted from three Moroccan aromatic plants.
 Methodology: Analysis of essential oils of Origanum compactum, Rosmarinus officinalis and Pelargonium asperum, collected from different localities in Morocco, were performed using a GC-MS spectrophotometry. Antibacterial activity was evaluated in vitro for five clinical multi-resistant isolates.
 Results: Origanum showed strong antibacterial activity against tested strains except Pseudomonas aeruginosa while Rosmarinum showed a bactericidal effect against Acinetobacter baumanii, Escherichia coli and Staphylococcus aureus. Pelargonium presented only slight growth inhibition of Staphylococcus aureus on solid medium, but provided bactericidal effect against Acinetobacter baumanii and Staphylococcus aureus. Interestingly, fractions F7 and F8 of Pelargonium which represented only 0.3% and 0.1% of the total mass were found bactericidal respectively against Klebsiella pneumoniae and Pseudomonas aeruginosa.
 Conclusions: Ours results showed that the antimicrobial activities were variables depending on the chemical composition of essential oils, the fraction used and the microorganism tested.Essential oils fractionation allows detection of bioactive substances, especially those owning antimicrobial activity, present in small quantities.

Activity of fosfomycin against nosocomial multiresistant bacterial pathogens from Croatia: a multicentric study.

AimTo determine in vitro susceptibility of multiresistant bacterial isolates to fosfomycin.MethodsIn this prospective in vitro study (local non-random sample, level of evidence 3), 288 consecutively collected multiresistant bacterial isolates from seven medical centers in Croatia were tested from February 2014 until October 2016 for susceptibility to fosfomycin and other antibiotics according to Clinical and Laboratory Standards Institute methodology. Susceptibility to fosfomycin was determined by agar dilution method, while disc diffusion were performed for in vitro testing of other antibiotics. Polymerase chain reaction and sequencing was performed for the majority of extended spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae (K. pneumoniae) and carbapenem-resistant isolates.ResultsThe majority of 288 multiresistant bacterial isolates (82.6%) were susceptible to fosfomycin. The 236 multiresistant Gram-negative isolates showed excellent susceptibility to fosfomycin. Susceptibility rates were as follows: Escherichia coli ESBL 97%, K. pneumoniae ESBL 80%, Enterobacter species 85.7%, Citrobacter freundii 100%, Proteus mirabilis 93%, and Pseudomonas aeruginosa 60%. Of the 52 multiresistant Gram-positive isolates, methicillin-resistant Staphylococcus aureus showed excellent susceptibility to fosfomycin (94.4%) and vancomycin-resistant enterococcus showed low susceptibility to fosfomycin (31%). Polymerase chain reaction analysis of 36/50 ESBL-producing K. pneumoniae isolates showed that majority of isolates had CTX-M-15 beta lactamase (27/36) preceded by ISEcp insertion sequence. All carbapenem-resistant Enterobacter and Citrobacter isolates had blaVIM-1 metallo-beta-lactamase gene.ConclusionWith the best in vitro activity among the tested antibiotics, fosfomycin could be an effective treatment option for infections caused by multiresistant Gram-negative and Gram-positive bacterial strains in the hospital setting.

Virulence gene profiles: alpha-hemolysin and clonal diversity in Staphylococcus aureus isolates from bovine clinical mastitis in China

BackgroundStaphylococcus aureus, a common cause of bovine mastitis, is known for its ability to acquire to antimicrobial resistance and to secrete numerous virulence factors that can exacerbate inflammation. In addition, alpha-hemolysin has an important role in S. aureus infections, diversity of the hla gene (that produces alpha-hmolysin) in S. aureus isolated from bovine mastitis has not been well characterized. The objective was, therefore, to determine diversity of virulence genes, hla gene sequences, and clonal profiles of S. aureus from bovine mastitis in Chinese dairy herds, and to evaluate inter-relationships.ResultsThe antimicrobials resistance varies from as low as 1.9% (2/103) for CTX to as high as 76.7% (79/103) for penicilin in the 103 isolates and 46 (44.7%) S. aureus were determined as multi-resistant isolates with diverse resistance patterns. Thirty-eight virulence gene patterns (with variable frequencies) were identified in the 103 isolates and correlated with MLST types, indicating a great diversity. Although the hla gene also had great diversity (14 genotypes), Hla peptides were relatively more conserved. With 7 clonal complexes identified from 24 spa types and 7 MLST types. Regarding the letter, ST 97 was the dominant type in S. aureus from bovine mastitis in China. Furthermore, based on phylogenetic analysis, there was a distinct evolutionary relationship between the hla gene and MLST.ConclusionMulti-resistant S. aureus occurred in bovine mastitis with diverse resistance patterns. The diversity of virulence gene profiles, especially the hla gene and, their relationship with molecular types were reported for the first time in S. aureus from bovine mastitis, which will be useful for future studies on immunogenicity and vaccine development. In addition, based on the distinct evolutionary relationship between the hla gene and MLST types, we inferred that the hla gene has potential role for molecular typing of S. aureus.

A novel synthetic peptide inspired on Lys49 phospholipase A2 from Crotalus oreganus abyssus snake venom active against multidrug-resistant clinical isolates

Currently, the evolving and complex mechanisms of bacterial resistance to conventional antibiotics are increasing, while alternative medicines are drying up, which urges the need to discover novel agents able to kill antibiotic-resistant bacteria. Lys49 phospholipase A2s (PLA2s) from snake venoms are multifunctional toxins able to induce a huge variety of therapeutic effects and consequently serve as templates for new drug leads. Hence, the present study was aimed at the synthesis of oligopeptides mimicking regions of the antibacterial Lys49 PLA2 toxin (CoaTx-II), recently isolated from Crotalus oreganus abyssus snake venom, to identify small peptides able to reproduce the therapeutic action of the toxin. Five peptides, representing major regions of interest within CoaTx-II, were synthesized and screened for their antibacterial properties. The 13-mer peptide pC-CoaTxII, corresponding to residues 115–129 of CoaTx-II, was able to reproduce the promising bactericidal effect of the toxin against multi-resistant clinical isolates. Peptide pC-CoaTxII is mainly composed by positively charged and hydrophobic amino acids, a typical trait in most antimicrobial peptides, and presented no defined secondary structure in aqueous environment. The physicochemical properties of pC-CoaTxII are favorable towards a strong interaction with anionic lipid membranes as those in bacteria. Additional in silico studies suggest formation of a water channel across the membrane upon peptide insertion, eventually leading to bacterial cell disruption and death. Overall, our findings confirm the valuable potential of snake venom toxins towards design and synthesis of novel antimicrobials, thus representing key insights towards development of alternative efficient antimicrobials to fight bacterial resistance to current antibiotics.

Detection of Salmonella spp. from zoo animals in Iran, determination of serovars, antibiotic susceptibility and genotyping by RAPD-PCR

Salmonellosis is an important food-borne bacterial zoonotic disease that affects both people and animals. Contamination sources include direct or indirect animal contact. We determined and measured the risk of Salmonella infection from zoo animal to human contact by isolation of Salmonella serovars from zoo animals kept at Karaj zoo park, Iran. Salmonella was isolated from 21 (20%) of the 104 anal swap samples. From the 21 collected samples 4, 7 and 10 were originated from birds, mammals and reptiles, respectively. Serotyping detected nine different serotypes including Enteritidis (n=4), Seftenberg (n=1), Typhimurium (n=4), Virchow (3), Berkeley (n=1), Kingabwa (n=2), Newport (n=2), Marina (n=2) and Havana (n=1). All the isolates except one (serovar Marina subspecies Hautenae IV) were belonged to Salmonella enterica subspecies enterica I. Salmonella enterica serotypes Typhimurium and Enteritidis were the most commonly detected serotypes. All the isolates tested, were resistant to one or more antibiotics and five isolates including the monkeys’ and long-eared owls’ isolates were multiresistant. RAPD profiles of each isolate produced with two different primers were identical. These finding shows highly contamination of zoo animals from Salmonella especially from the multiresistant isolates. All of the animals in the zoo, pet owners, veterinarians, zookeepers and visitors are at high risk of salmonellosis with reptiles being the most important source of infection.

Composition and antimicrobial resistance profile of Gram‐negative microbiota prevalent in aquacultured fish

AbstractAquatic environments are one of the most favorable settings for acquisition and dissemination of antimicrobial resistance. The aims of this study were twofold: (1) to isolate and identify antimicrobial resistant Gram‐negative bacteria that are prevalent in fish kept in open aquaculture ponds and (2) to analyse their antimicrobial resistance profiles. One hundred and nineteen isolates from fish resistant to at least one antimicrobial were investigated. The most predominant genera were Pseudomonas, Chryseobacterium, Enterobacteriaceae, and Aeromonas. The highest numbers of multiresistant isolates were found within Pseudomonas spp., and the lowest, in Aeromonas spp. Resistance to beta‐lactams was the most common among all of the bacterial genera. The absence or very low rates of resistance to fluoroquinolones, the small number of clinically important resistance genes, and bacterial taxonomic composition suggest that the most widespread resistant bacteria in aquacultured fish are autochthonous microbiota.Practical applicationsThe majority of antimicrobial resistant bacteria that are prevalent in aquacultured fish from open ponds can be treated as natural (autochthonous microbiota). In this study, only a minority of resistant bacteria detected in fish could be associated with polluted waters originating from animal farms or human healthcare facilities. Some strains, particularly the family Enterobacteriaceae that is found in fish, contain clinically important resistance determinants that potentially can be transmitted to human microbiota in cases of inappropriate processing of fish intended for food. With regard to antimicrobial resistant bacteria, measures for control of inflowing waters to aquaculture ponds should be taken in addition to monitoring fish microbiota and its’ resistance should be investigated on a regular basis.

Prevalencia de Salmonella spp., en ganglios mesentéricos de porcinos en plantas de beneficio Colombianas

Objetivo. El objetivo fue determinar la prevalencia de Salmonella spp., en ganglios mesentéricos de porcinos, provenientes de diferentes regiones de Colombia. Materiales y Métodos. Se realizó un muestreo estratificado por fijación proporcional en plantas de beneficio, de cada uno de los 13 departamentos participantes, cuyo volumen de producción de carne de cerdo es representativo a nivel nacional. El muestreo se realizó durante cinco meses, para un total de 457 muestras analizadas. La identificación de Salmonella spp., se realizó mediante el Sistema Molecular MDS, luego los aislamientos fueron confirmados por Maldi-TOF MS. Se determinó la susceptibilidad antimicrobiana de los aislamientos usando el panel B1016-180 y el análisis estadístico se realizó en Whonet 2016, posteriormente algunos de los aisalmientos multi-resistentes fueron serotipificados por el método de Kauffman-White. Resultados. La prevalencia nacional fue 28.2%, con presencia de los serotipos S. Typhimurium, S. Agama, S. London, S. Agona, S. Haifa y S. 1,4,12: i : --. Se encontró resistencia a antibióticos de uso frecuente en humanos (23.6% Trimetoprim/Sulfametoxazol, 2.7% Cefotaxime (CTX), 11.8% Ampicilina (AMP) y 1.8% Ciprofloxacina). Conclusión. La prevalencia de Salmonella en ganglios mesénticos fue del 28.2%, siendo la región del Huila la que más aportó, se recuperaron serotipos atípicos como S. London y S. Haifa

Antimycobacterial activity of veterinary antibiotics (Apramycin and Framycetin) against Mycobacterium abscessus: Implication for patients with cystic fibrosis.

Antimicrobial resistance has rendered certain species of Mycobacterium difficult to treat clinically, particularly the nontuberculous Mycobacterium and Mycobacterium abscessus. While veterinary medicine and human medicine share many classes of antibiotics, there are several antibiotics which are uniquely licensed to veterinary medicine but not human medicine. It was, therefore, the aim of this study to examine the action of eight veterinary antibiotics to a population of multi- and pan-resistant M. abscessus, isolated from the sputum of patients with cystic fibrosis (CF). Antibiotic susceptibility studies were performed on human clinical isolates of M. abscessus (n = 16), including 11 smooth isolates, 4 rough isolates, and 1 reference isolate (NCTC 13031), against the following 7 veterinary antibiotics (antibiotic class): apramycin (aminoglycoside), cefovecin (cephalosporin), ceftiofur (cephalosporin), framycetin (aminoglycoside), lincomycin (lincosamide), pirlimycin (lincosamide), and spectinomycin (aminocyclitol). M. abscessus isolates were sensitive (100%) to apramycin and framycetin but resistant (100%) to cefovecin, ceftiofur, lincomycin, pirlimycin, and spectinomycin. This study identified that the veterinary aminoglycosides, apramycin, and framycetin, have in vitro activity against multi-resistant clinical isolates of M. abscessus. Further studies should now compare the activity of these antibiotics against amikacin and the human aminoglycoside, advocated in the treatment of disease in CF patients, to determine if these novel antibiotics have a future role for the development in human medicine with such chronic disease patients.

Multidrug-Resistant Bacterial Pathogens Assessment in Canine Ophthalmic Infections

The objective of this study was to identify the main microorganisms associated with ophthalmic infections and determine the resistance profile of these isolates against antimicrobial drugs. 26 bacterial isolates from 18 canine ophthalmic infections were submited to the phenotypic resistance profile for 36 drugs of 12 classes of antimicrobials, research of multidrug-resistant strains with importance in public health and detection of Staphylococcus mecA gene by PCR. The bacterial isolates were identified as Staphylococcus spp. (n = 18), Enterococcus spp. (n = 1), enterobacteria (n = 6) and Pseudomonas spp. (n = 1). The percentage of resistance and intermediate resistance were 42.48% (n = 325). Considering separate antimicrobials drugs, 18 isolates were characterized by multidrug resistant, while by the assesment of resistance to class, 20 isolates were multiresistant. In the phenotypic detection, 61.11% (11/18) of Staphylococcus spp. were predicted by Methicillin-Resistant Staphyloccus (MRS), whereas the genotypic detection, 38.89% (7/18) were carriers of the mecA gene. Two enterobacterias were considered producers of expectro Extended of Betalactamase (ESBL). EUCAST was more reliable for detecting MRS strains than the CLSI. The present study detected multiresistant isolates of great importance and are involved in cases of public health, such as MRS, MRSMLSb, ESBL, very important to be readily identified and controled so as to prevent the spread of this type of resistance.

Antibiotic Resistance of Acinetobacter spp. Isolates from the River Danube: Susceptibility Stays High.

Acinetobacter spp. occur naturally in many different habitats, including food, soil, and surface waters. In clinical settings, Acinetobacter poses an increasing health problem, causing infections with limited to no antibiotic therapeutic options left. The presence of human generated multidrug resistant strains is well documented but the extent to how widely they are distributed within the Acinetobacter population is unknown. In this study, Acinetobacter spp. were isolated from water samples at 14 sites of the whole course of the river Danube. Susceptibility testing was carried out for 14 clinically relevant antibiotics from six different antibiotic classes. Isolates showing a carbapenem resistance phenotype were screened with PCR and sequencing for the underlying resistance mechanism of carbapenem resistance. From the Danube river water, 262 Acinetobacter were isolated, the most common species was Acinetobacter baumannii with 135 isolates. Carbapenem and multiresistant isolates were rare but one isolate could be found which was only susceptible to colistin. The genetic background of carbapenem resistance was mostly based on typical Acinetobacter OXA enzymes but also on VIM-2. The population of Acinetobacter (baumannii and non-baumannii) revealed a significant proportion of human-generated antibiotic resistance and multiresistance, but the majority of the isolates stayed susceptible to most of the tested antibiotics.