Influence of occupational exposure to pigs or chickens on human gut microbiota composition in Thailand.

Pig farming's influence on human gut microbiota has been observed previously, but its pervasiveness is unclear. We therefore aimed at studying whether pig farming influenced human gut microbiota composition in Thailand and whether poultry farming did too. We collected human stool samples (71 pig farmers, 131 chicken farmers, 55 non-farmers) for 16S rRNA sequencing and performed subsequent DADA2 analyses of amplicon sequence variants. We found that Alpha diversity values were highest among chicken farmers. Relative abundances of Prevotellaceae were significantly higher among pig farmers than among chicken farmers and non-farmers (p < 0.001). Beta diversity plots revealed different clustering according to occupation. The presence or absence of antimicrobial-resistant Escherichia coli was not associated with changes in gut microbiota composition. In conclusion, occupation was the strongest factor influencing gut microbiota composition in Thailand. We hypothesize that Prevotellaceae amplicon sequence variants are transmitted from pigs to pig farmers

Optical dna mapping of plasmids reveals clonal spread of carbapenem-resistant klebsiella pneumoniae in a large thai hospital

Carbapenem-resistant Klebsiella pneumoniae (CR-KP) in patients admitted to hospitals pose a great challenge to treatment. The genes causing resistance to carbapenems are mostly found in plasmids, mobile genetic elements that can spread easily to other bacterial strains, thus exacerbating the problem. Here, we studied 27 CR-KP isolates collected from different types of samples from 16 patients admitted to the medical ward at Siriraj Hospital in Bangkok, Thailand, using next generation sequencing (NGS) and optical DNA mapping (ODM). The majority of the isolates belonged to sequence type (ST) 16 and are described in detail herein. Using ODM, we identified the plasmid carrying the blaNDM-1 gene in the ST16 isolates and the plasmids were very similar, highlighting the possibility of using ODM of plasmids as a surrogate marker of nosocomial spread of bacteria. We also demonstrated that ODM could identify that the blaCTX-M-15 and blaOXA-232 genes in the ST16 isolates were encoded on separate plasmids from the blaNDM-1 gene and from each other. The other three isolates belonged to ST147 and each of them had distinct plasmids encoding blaNDM-1

Comparative pharmacodynamics of four different carbapenems in combination with polymyxin B against carbapenem-resistant Acinetobacter baumannii

The objective of this study was to determine the comparative pharmacodynamics of four different carbapenems in combination with polymyxin B (PMB) against carbapenem-resistant Acinetobacter baumannii isolates using time–kill experiments at two different inocula. Two A. baumannii strains (03-149-1 and N16870) with carbapenem minimum inhibitory concentrations (MICs) ranging from 8 to 64 mg/L were investigated in 48-h time–kill experiments using starting inocula of 106 CFU/mL and 108 CFU/mL. Concentration arrays of ertapenem, doripenem, meropenem and imipenem at 0.25×, 0.5×, 1×, 1.5× and 2× published maximum serum concentration (Cmax) values (Cmax concentrations of 12, 21, 48 and 60 mg/L, respectively) were investigated in the presence of 1.5 mg/L PMB. Use of carbapenems without PMB resulted in drastic re-growth. All carbapenem combinations were able to achieve a ≥3 log10 CFU/mL reduction by 4 h against both strains at 106 CFU/mL, whereas maximum reductions against strain 03-149-1 at 108 CFU/mL were 1.0, 3.2, 2.2 and 3.3 log10 CFU/mL for ertapenem, doripenem, meropenem and imipenem, respectively. None of the combinations were capable of reducing 108 CFU/mL of N16870 by ≥2 log10 CFU/mL. Ertapenem combinations consistently displayed the least activity, whereas doripenem, meropenem and imipenem combinations had similar activities that were poorly predicted by carbapenem MICs. As doripenem, meropenem, or imipenem displayed similar pharmacodyanmics in combination, the decision of which carbapenem to use in combination with PMB may be based on toxicodynamic profiles if drastic discordance in MICs is not present

Paradoxical Effect of Polymyxin B: High Drug Exposure Amplifies Resistance in Acinetobacter baumannii

ABSTRACT Administering polymyxin antibiotics in a traditional fashion may be ineffective against Gram-negative ESKAPE ( Enterococcus faecium , Staphylococcus aureus , Klebsiella pneumoniae , Acinetobacter baumannii , Pseudomonas aeruginosa , and Enterobacter species) pathogens. Here, we explored increasing the dose intensity of polymyxin B against two strains of Acinetobacter baumannii in the hollow-fiber infection model. The following dosage regimens were simulated for polymyxin B ( t 1/2 = 8 h): non-loading dose (1.43 mg/kg of body weight every 12 h [q12h]), loading dose (2.22 mg/kg q12h for 1 dose and then 1.43 mg/kg q12h), front-loading dose (3.33 mg/kg q12h for 1 dose followed by 1.43 mg/kg q12h), burst (5.53 mg/kg for 1 dose), and supraburst (18.4 mg/kg for 1 dose). Against both A. baumannii isolates, a rapid initial decline in the total population was observed within the first 6 h of polymyxin exposure, whereby greater polymyxin B exposure resulted in greater maximal killing of −1.25, −1.43, −2.84, −2.84, and −3.40 log 10 CFU/ml within the first 6 h. Unexpectedly, we observed a paradoxical effect whereby higher polymyxin B exposures dramatically increased resistant subpopulations that grew on agar containing up to 10 mg/liter of polymyxin B over 336 h. High drug exposure also proliferated polymyxin-dependent growth. A cost-benefit pharmacokinetic/pharmacodynamic relationship between 24-h killing and 336-h resistance was explored. The intersecting point, where the benefit of bacterial killing was equal to the cost of resistance, was an f AUC 0–24 (area under the concentration-time curve from 0 to 24 h for the free, unbound fraction of drug) of 38.5 mg · h/liter for polymyxin B. Increasing the dose intensity of polymyxin B resulted in amplification of resistance, highlighting the need to utilize polymyxins as part of a combination against high-bacterial-density A. baumannii infections

Perspectives on antimicrobial use in pig and layer farms in thailand: legislation, policy, regulations and potential

Irrational use of antimicrobials is a major problem worldwide. The comprehensiveness of the existing legislation and veterinary pharmaceutical regulatory system has been critically evaluated and its practical implementation was assessed in this study. A cross-sectional survey study, and an in-depth interview of key informants involving the layer and pig farm owners/managers of farms located in Chiang Mai, Lamphun and Chonburi Provinces were conducted. The Thai FDA is responsible for pre-marketing and authorizes relevant officials of DLD to enforce drug acts related to the post-marketing of veterinary drugs/biologics. These existing legislations and regulations were comprehensive enough to cover all areas of pharmaceutical activities developed to protect the health of the public and animals in the country; however, the enforcement of these rules may not be properly enforced or may be ineffectively executed. Rules regarding veterinary pharmaceuticals being distributed throughout the country have not been clearly stated. Farmers can easily access veterinary pharmaceuticals, and veterinarian prescriptions were not needed. Additionally, the relevant benefits were among the most important reasons for choosing to use antimicrobials on farms, along with a lack of availability of better alternative products for the treatment of infections. Intensive legislation and regulation enforcement were considered to be the most effective means of reducing antimicrobial usage and abuse in Thailand

Polymyxin-resistant, carbapenem-resistant Acinetobacter baumannii is eradicated by a triple combination of agents that lack individual activity

Objectives: The emergence of polymyxin resistance threatens to leave clinicians with few options for combatting drug-resistant Acinetobacter baumannii . The objectives of the current investigation were to define the in vitro emergence of polymyxin resistance and identify a combination regimen capable of eradicating A. baumannii with no apparent drug susceptibilities. Methods: Two clonally related, paired, A. baumannii isolates collected from a critically ill patient who developed colistin resistance while receiving colistin methanesulfonate in a clinical population pharmacokinetic study were evaluated: an A. baumannii isolate collected before (03-149.1, polymyxin-susceptible, MIC 0.5 mg/L) and an isolate collected after (03-149.2, polymyxin-resistant, MIC 32 mg/L, carbapenem-resistant, ampicillin/sulbactam-resistant). Using the patient's unique pharmacokinetics, the patient's actual regimen received in the clinic was recreated in a hollow-fibre infection model (HFIM) to track the emergence of polymyxin resistance against 03-149.1. A subsequent HFIM challenged the pan-resistant 03-149.2 isolate against polymyxin B, meropenem and ampicillin/sulbactam alone and in two-drug and three-drug combinations. Results: Despite achieving colistin steady-state targets of an AUC 0-24 >60 mg·h/L and C avg of >2.5 mg/L, colistin population analysis profiles confirmed the clinical development of polymyxin resistance. During the simulation of the patient's colistin regimen in the HFIM, no killing was achieved in the HFIM and amplification of polymyxin resistance was observed by 96 h. Against the polymyxin-resistant isolate, the triple combination of polymyxin B, meropenem and ampicillin/sulbactam eradicated the A. baumannii by 96 h in the HFIM, whereas monotherapies and double combinations resulted in regrowth. Conclusions: To combat polymyxin-resistant A. baumannii , the triple combination of polymyxin B, meropenem and ampicillin/sulbactam holds great promise

Global metabolic analyses identify key differences in metabolite levels between polymyxin-susceptible and polymyxin-resistant Acinetobacter baumannii

Multidrug-resistant Acinetobacter baumannii presents a global medical crisis and polymyxins are used as the last-line therapy. This study aimed to identify metabolic differences between polymyxin-susceptible and polymyxin-resistant A. baumannii using untargeted metabolomics. The metabolome of each A. baumannii strain was measured using liquid chromatography-mass spectrometry. Multivariate and univariate statistics and pathway analyses were employed to elucidate metabolic differences between the polymyxin-susceptible and -resistant A. baumannii strains. Significant differences were identified between the metabolic profiles of the polymyxin-susceptible and -resistant A. baumannii strains. The lipopolysaccharide (LPS) deficient, polymyxin-resistant 19606R showed perturbation in specific amino acid and carbohydrate metabolites, particularly pentose phosphate pathway (PPP) and tricarboxylic acid (TCA) cycle intermediates. Levels of nucleotides were lower in the LPS-deficient 19606R. Furthermore, 19606R exhibited a shift in its glycerophospholipid profile towards increased abundance of short-chain lipids compared to the parent polymyxin-susceptible ATCC 19606. In contrast, in a pair of clinical isolates 03–149.1 (polymyxin-susceptible) and 03–149.2 (polymyxin-resistant, due to modification of lipid A), minor metabolic differences were identified. Notably, peptidoglycan biosynthesis metabolites were significantly depleted in both of the aforementioned polymyxin-resistant strains. This is the first comparative untargeted metabolomics study to show substantial differences in the metabolic profiles of the polymyxin-susceptible and -resistant A. baumannii

High-intensity meropenem combinations with polymyxin B: new strategies to overcome carbapenem resistance in Acinetobacter baumannii

The pharmacodynamics of polymyxin/carbapenem combinations against carbapenem-resistant Acinetobacter baumannii (CRAB) are largely unknown. Our objective was to determine whether intensified meropenem regimens in combination with polymyxin B enhance killing and resistance suppression of CRAB

Quality indicators for responsible antibiotic use in the inpatient setting: a systematic review followed by an international multidisciplinary consensus procedure

Background This study was conducted as part of the Driving Reinvestment in Research and Development and Responsible Antibiotic Use (DRIVE-AB) project and aimed to develop generic quality indicators (QIs) for responsible antibiotic use in the inpatient setting. Methods A RAND-modified Delphi method was applied. First, QIs were identified by a systematic review. A complementary search was performed on web sites of relevant organizations. Duplicates were removed and disease and patient-specific QIs were combined into generic indicators. The relevance of these QIs was appraised by a multidisciplinary international stakeholder panel through two questionnaires and an in-between consensus meeting. Results The systematic review retrieved 70 potential generic QIs. The QIs were appraised by 25 international stakeholders with diverse backgrounds (medical community, public health, patients, antibiotic research and development, regulators, governments). Ultimately, 51 QIs were selected in consensus. QIs with the highest relevance score included: (i) an antibiotic plan should be documented in the medical record at the start of the antibiotic treatment; (ii) the results of bacteriological susceptibility testing should be documented in the medical record; (iii) the local guidelines should correspond to the national guidelines but should be adapted based on local resistance patterns; (iv) an antibiotic stewardship programme should be in place at the healthcare facility; and (v) allergy status should be taken into account when antibiotics are prescribed. Conclusions This systematic and stepwise method combining evidence from literature and stakeholder opinion led to multidisciplinary international consensus on generic inpatient QIs that can be used globally to assess the quality of antibiotic use