Pinpointing environmental antibiotic resistance (AR) hot spots in low-and middle-income countries (LMICs) is hindered by a lack of available and comparable AR monitoring data relevant to such settings. Addressing this problem, we performed a comprehensive spatial and seasonal assessment of water quality and AR conditions in a Malaysian river catchment to identify potential "simple" surrogates that mirror elevated AR. We screened for resistant coliforms, 22 antibiotics, 287 AR genes and integrons, and routine water quality parameters, covering absolute concentrations and mass loadings. To understand relationships, we introduced standardized "effect sizes" (Cohen's D) for AR monitoring to improve comparability of field studies. Overall, water quality generally declined and environmental AR levels increased as one moved down the catchment without major seasonal variations, except total antibiotic concentrations that were higher in the dry season (Cohen's D > 0.8, P < 0.05). Among simple surrogates, dissolved oxygen (DO) most strongly correlated (inversely) with total AR gene concentrations (Spearman's ρ 0.81, P < 0.05). We suspect this results from minimally treated sewage inputs, which also contain AR bacteria and genes, depleting DO in the most impacted reaches. Thus, although DO is not a measure of AR, lower DO levels reflect wastewater inputs, flagging possible AR hot spots. DO measurement is inexpensive, already monitored in many catchments, and exists in many numerical water quality models (e.g., oxygen sag curves). Therefore, we propose combining DO data and prospective modeling to guide local interventions, especially in LMIC rivers with limited data.
Matched MeSH terms: Drug Resistance, Microbial/genetics
From an extensive search of one of the largest inpatient leprosaria in the world, at Sungei Buloh, Malaysia, nine patients with lepromatous leprosy were discovered who gave prima facie evidence of sulfone resistance. The evidence was based on a failure to show clinical improvement over at least five years despite treatment with sulfones and an absence of a satisfactory fall in the bacteriologic (BI) or the morphologic (MI) index. The selected patients were admitted to our Research Unit for (a) a further six month, rigorously controlled, trial period on DDS (as injectable sulfone, 300 mgm. twice weekly) and (b) DDS sensitivity tests, based on use of the foot pad infection in mice with bacilli obtained from skin biopsies. The response of the nine patients to the six month trial period on DDS was assessed clinically, bacteriologically and histologically, and revealed that only four of the patients failed to respond satisfactorily. Furthermore, the sensitivity tests in the mouse foot pad infection showed that only the strains of M. leprae from the four patients who failed to improve were insensitive to DDS. Thus there was a good correlation between the results of the clinical and experimental studies and for the first time direct proof for the existence of DDS resistant strain s of M. leprae. The MI proved to be the most sensitive of the assessments used to determine the response of the selected patients to a trial period on DDS. The histology of patients with drug resistance is essentially that of relapsing or very acute leprosy. Its features have much in common with those of "histoid" lesions, the latter being distinguished mainly by the absence of cytologic maturation. Classification is complicated by the presence of borderline features in otherwise lepromatous lesions.
The first three patients with proven DDS-resistant leprosy infections were treated for one year with the riminophenazine
derivative B.663 (300 mgm. daily for six days a week). All of them showed satisfactory clinical, bacteriologic and histologic
improvement, which at the time of writing has been maintained for a total period of 28 months. The results show that
active leprosy resulting from resistance to one drug can still respond satisfactorily to a different type of drug, as is the case with drug resistance in other bacterial infections. In this limited study B.663 showed no toxicity, but the degree of skin discoloration was disconcerting to Chinese patients.
Aquaculture systems are highly complex, dynamic and interconnected systems influenced by environmental, biological, cultural, socio-economic and human behavioural factors. Intensification of aquaculture production is likely to drive indiscriminate use of antibiotics to treat or prevent disease and increase productivity, often to compensate for management and husbandry deficiencies. Surveillance or monitoring of antibiotic usage (ABU) and antibiotic resistance (ABR) is often lacking or absent. Consequently, there are knowledge gaps for the risk of ABR emergence and human exposure to ABR in these systems and the wider environment. The aim of this study was to use a systems-thinking approach to map two aquaculture systems in Vietnam - striped catfish and white-leg shrimp - to identify hotspots for emergence and selection of resistance, and human exposure to antibiotics and antibiotic-resistant bacteria. System mapping was conducted by stakeholders at an interdisciplinary workshop in Hanoi, Vietnam during January 2018, and the maps generated were refined until consensus. Thereafter, literature was reviewed to complement and cross-reference information and to validate the final maps. The maps and component interactions with the environment revealed the grow-out phase, where juveniles are cultured to harvest size, to be a key hotspot for emergence of ABR in both systems due to direct and indirect ABU, exposure to water contaminated with antibiotics and antibiotic-resistant bacteria, and duration of this stage. The pathways for human exposure to antibiotics and ABR were characterised as: occupational (on-farm and at different handling points along the value chain), through consumption (bacterial contamination and residues) and by environmental routes. By using systems thinking and mapping by stakeholders to identify hotspots we demonstrate the applicability of an integrated, interdisciplinary approach to characterising ABU in aquaculture. This work provides a foundation to quantify risks at different points, understand interactions between components, and identify stakeholders who can lead and implement change.
Matched MeSH terms: Drug Resistance, Microbial/genetics*
A study was carried out to investigate the presence of bacteria flora in wild mud crab (Scylla serrata) from Setiu Wetland as well as their antibiotic resistances. A total of 91 bacterial isolates consisting of 12 bacterial species were successfully isolated from mud crab. Oxolinic acid was found to be effective against all the bacterial isolates whilst the highest percentage of antibiotic resistance was shown by lincomycin (94.5%) followed by ampicillin (90.1%), amoxicillin (86.8%) and oleandomycin (78.0%). The study is very useful to evaluate the safety of mud crab for human consumption based on wild mud crab-associated bacteria as well as their antibiotic resistances.
Enterobacteriaceae isolated from clinical sources were examined for antibiotic resistance and the ability to transfer resistance to Escherichia coli. Twenty-nine out of 80 strains tested transferred part or all oftheir resistance genes. The strains carrying R plasmids included the genera Escherichia, Klebsiella, Salmonella, Enterobacter, Proteus, Providencia and Citrobacter. These results indicate that R plasmids possibly play a major role in the emergence of antibiotic resistance among clinical isolates of Enterobacteriaceae.
Inappropriate use of antibiotics in animal production system is one of the major factors leading to the antibiotic resistance (ABR) development. In Vietnam, the ABR situation is crucial as antibiotics have been used indiscriminately for disease prevention and as growth promoters in animals. Thus, a thorough understanding on the ABR in veterinary settings would be beneficial to the Vietnam public health authority in formulating timely interventions. This review aimed to provide information on the current status of antibiotic usage in animal husbandry in Vietnam, identified gaps in research, and suggested possible solutions to tackle ABR. To this end, data on ABR in animals were extracted from 3 major electronic databases (PubMed, Web of Science, and ScienceDirect) in the period of January 2013-December 2020. The review findings were reported according to PRISMA, which highlighted the emergence and persistence of ABR in bacterial isolates, including Escherichia coli, Enterococcus spp., and Salmonella species, obtained from pigs and poultry. The lack of awareness of Vietnamese farmers on the antibiotic utilization guidelines was one of the main causes driving the animal ABR. Hence, this paper calls for interventions to restrict antibiotics use in food-producing animals by national action plan and antibiotics control programs. Additionally, studies to evaluate knowledge, attitude, and practice (KAP) of the community are required to promote rational use of antibiotics in all sectors.
Enterococcus faecalis is known to cause a variety of nosocomial infections, including urinary tract infections. Antibiotic resistance and virulence properties in this species are of public concern. The draft genome sequences of six E. faecalis strains isolated from clinical and environmental sources in Malaysia are presented here.
Hospital wastewater has emerged as a major category of environmental pollutants over the past two decades, but its prevalence in freshwater is less well documented than other types of contaminants. Due to compound complexity and improper operations, conventional treatment is unable to remove pharmaceuticals from hospital wastewater. Advanced treatment technologies may eliminate pharmaceuticals, but there are still concerns about cost and energy use. There should be a legal and regulatory framework in place to control the flow of hospital wastewater. Here, we review the latest scientific knowledge regarding effective pharmaceutical cleanup strategies and treatment procedures to achieve that goal. Successful treatment techniques are also highlighted, such as pre-treatment or on-site facilities that control hospital wastewater where it is used in hospitals. Due to the prioritization, the regulatory agencies will be able to assess and monitor the concentration of pharmaceutical residues in groundwater, surface water, and drinking water. Based on the data obtained, the conventional WWTPs remove 10-60% of pharmaceutical residues. However, most PhACs are eliminated during the secondary or advanced therapy stages, and an overall elimination rate higher than 90% can be achieved. This review also highlights and compares the suitability of currently used treatment technologies and identifies the merits and demerits of each technology to upgrade the system to tackle future challenges. For this reason, pharmaceutical compound rankings in regulatory agencies should be the subject of prospective studies.
As the causative agent of foodborne related illness, Vibrio species causes a huge impact on the public health and management. Vibrio species is often associated with seafood as the latter plays a role as a vehicle to transmit bacterial infections. Hence, antibiotics are used not to promote growth but rather to prevent and treat bacterial infections. The extensive use of antibiotics in the aquaculture industry and environment has led to the emerging of antibiotic resistant strains. This phenomenon has triggered an alarming public health concern due to the increase number of pathogenic Vibrio strains that are resistant to clinically used antibiotics and is found in the environment. Antibiotic resistance and the genes location in the strains can be detected through plasmid curing assay. The results derived from plasmid curing assay is fast, cost effective, sufficient in providing insights, and influence the antibiotic management policies in the aquaculture industry. This presentation aims in discussing and providing insights on various curing agents in Vibrio species. To our best of knowledge, this is a first review written discussing on plasmid curing in Vibrio species.
Carbapenem resistant Enterobacteriaceae (CRE) pose an urgent risk to global human health. CRE that are non-susceptible to all commercially available antibiotics threaten to return us to the pre-antibiotic era. Using Single Molecule Real Time (SMRT) sequencing we determined the complete genome of a pandrug-resistant Klebsiella pneumoniae isolate, representing the first complete genome sequence of CRE resistant to all commercially available antibiotics. The precise location of acquired antibiotic resistance elements, including mobile elements carrying genes for the OXA-181 carbapenemase, were defined. Intriguingly, we identified three chromosomal copies of an ISEcp1-bla(OXA-181) mobile element, one of which has disrupted the mgrB regulatory gene, accounting for resistance to colistin. Our findings provide the first description of pandrug-resistant CRE at the genomic level, and reveal the critical role of mobile resistance elements in accelerating the emergence of resistance to other last resort antibiotics.
Campylobacter jejuni is a frequent cause of human bacterial gastrointestinal foodborne disease worldwide. Antibiotic resistance in this species is of public health concern. The draft genome sequences of three multiantibiotic-resistant C. jejuni strains (2865, 2868, and 2871) isolated from poultry at retail outlets in Malaysia are presented here.
Enterotoxin production by strains of Staphylococcus aureus isolated from foods unconnected with outbreaks offood poisoning was investigated. Twenty-three percent of 217 strains examined produced enterotoxins A, B, C, D or E. Enterotoxin C was found to occur most frequently. Enterotoxin A was not detected alone from any of the strains examined, but occurred together with other enterotoxins. The overall number of strains isolated from raw foods which produced one or more enterotoxins was higher than that for cooked foods. Antibiotic sensitivities were unrelated to enterotoxin production and no correlation could be found between methicillin resistance and enterotoxigenicity.
Forty samples of Malaysian cooked foods were examined for the presence of antibiotic-resistant coliforms and R plasmids. Twenty seven (68%) of the foods had antibiotic-resistant coliforms and 5 (13%) had R plasmids. Nineteen samples (48%) had total bacterial counts over 10(6) per gm and in 5 samples, no coliforms were detected. Our findings show that cooked food may be one possible way by which R plasmids are spread. The control of the spread of R plasmids is discussed.