|Year : 2018 | Volume
| Issue : 3 | Page : 257-260
Interaction of South Asian spices with conventional antibiotics: Implications for antimicrobial resistance for Mycobacterium abscessus and cystic fibrosis
Rachel Ellen Moore1, Beverley Cherie Millar2, Jayachandran R Panickar3, John E Moore2
1 Department of Bacteriology, Northern Ireland Public Health Laboratory, Belfast City Hospital, Belfast, Northern Ireland, United Kingdom
2 Department of Bacteriology, Northern Ireland Public Health Laboratory, Belfast City Hospital, Belfast; School of Biomedical Sciences, Ulster University, Coleraine; Centre for Experimental Medicine, Queen's University, Belfast, Northern Ireland, United Kingdom
3 Department of Paediatrics, Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates
|Date of Web Publication||6-Sep-2018|
Prof. John E Moore
Department of Bacteriology, Northern Ireland Public Health Laboratory, Belfast City Hospital, Belfast-BT9. 7AD, Northern Ireland
Source of Support: None, Conflict of Interest: None
Background: Antimicrobial resistance (AMR) has rendered certain species of Mycobacterium difficult to treat clinically, particularly, the nontuberculous Mycobacterium, Mycobacterium abscessus. This bacterium is emerging in specific disease populations, including amongst cystic fibrosis (CF) patients, where AMR represent a true treatment dilemma. Therefore, any innovation with traditional antimicrobial compounds in spices, which increases the potency of existing conventional antibiotics should be investigated. Methods: M. abscessus isolates (n = 9 multidrug-resistant clinical isolates from CF patients + 1 Reference Strain) were examined for their direct susceptibility to 27 spices, as well as the interactive effect of this spice combination to their susceptibility to amikacin and linezolid antibiotic, with standard disk diffusion assay. Results: Five isolates of M. abscessus (5/10; 50%) failed to grow on the spice enriched medium, which included four clinical isolates and the National Culture Type Collection (NCTC) Reference Strain. Of the remaining five isolates which grew on the spice medium, no cultural phenotypic differences were observed, compared to unsupplemented controls. In the case of both amikacin and linezolid, the zone of inhibition increased with the inclusion of the spices. Initially, all isolates of M. abscessus were fully resistant to linezolid (mean zone of inhibition = 0 mm), and growth was to the edge of the antibiotic disk, whereas when in the presence of spices, large zones of inhibition were observed (mean zone of inhibition = 33.3 mm). With amikacin, the mean zone of inhibition increased from 23.2 mm to 32.0 mm, in the presence of spices. Conclusion: These data suggest that the spices were interacting synergistically with the antibiotics, thus making the antibiotic more potent against the bacteria tested. This study is significant as it demonstrates a positive interaction between spices and the conventional antimycobacterial antibiotics, amikacin, and linezolid. Given the burden of AMR to M. abscessus, particularly in a patient with chronic disease such as CF, any food-related innovation that can help maximize the potency of existing antimycobacterial antibiotics is to be encouraged and developed. The specific mechanism as to how spices increase the potency of such antibiotics with M. abscessus needs to be elucidated, as well as novel food (spice) delivery modalities developed, including novel medicinal foodstuffs or functional foods, that can harness this beneficial effect in vivo to medicine and society.
Keywords: Antimicrobial resistance, cystic fibrosis, infection, Mycobacterium abscessus, nontuberculous Mycobacteria
|How to cite this article:|
Moore RE, Millar BC, Panickar JR, Moore JE. Interaction of South Asian spices with conventional antibiotics: Implications for antimicrobial resistance for Mycobacterium abscessus and cystic fibrosis. Int J Mycobacteriol 2018;7:257-60
|How to cite this URL:|
Moore RE, Millar BC, Panickar JR, Moore JE. Interaction of South Asian spices with conventional antibiotics: Implications for antimicrobial resistance for Mycobacterium abscessus and cystic fibrosis. Int J Mycobacteriol [serial online] 2018 [cited 2019 Mar 22];7:257-60. Available from: http://www.ijmyco.org/text.asp?2018/7/3/257/240693
| Introduction|| |
Historically, spices have been used around the world to flavor, create aroma, color, and preserve foodstuffs. The antimicrobial properties of spices have been well documented in the published scientific/medical literature, as recently reviewed in the seminal review by Liu et al.
The long-term use of several classes of antibiotic agents, including aminoglycosides, beta-lactams, fluoroquinolones, macrolides, and polymyxin, for the prophylaxis, maintenance, and treatment of bacterial respiratory pathogens causing chronic chest infections in patients with cystic fibrosis (CF) has important consequences for the persistence of respiratory pathogens, including the emerging nontuberculous Mycobacteria (NTM), in particular, Mycobacterium abscessus. M. abscessus infection is CF has gradually emerged from early reports of its prevalence of 1.3% in 1984 to 32.7% in adult CF patients in the US, although prevalence rates from the US CF Foundation Registry are 12%. This infection is associated with chronic persistence of the organism in the lower airways, once colonization has occurred, leading to increased morbidity and mortality in some patients. Furthermore, the presence of this organism in patients' sputum is usually a contraindication for lung transplantation. Hence, it is important to be have efficacious antibiotics available to attempt to eradicate the organism on the first isolation from sputum, as well as to chronically manage the organism, particularly with acute pulmonary exacerbation. One worrying microbiological characteristic to emerge from studies to date is the relative antibiotic resistance of this organism, where there is usually a high degree of antibiotic resistance to several classes of antibiotics.
While there are several reports on the antibacterial activity of spices on other species of Mycobacterium, particularly M. tuberculosis,, there have been no reports on the activity of spices on M. abscessus. Therefore, it was the aim of the current study to explore potential antimycobacterial activity of South Asian spices, by examining: (i) a direct antibacterial effect of spices on growth and proliferation of M. abscessus isolates and (ii) to investigate if the presence of a wide variety of spices alter antimicrobial activity of two commonly used antibiotics (amikacin and linezolid), in the treatment of M. abcessus pulmonary infection.
| Methods|| |
Spices employed in this study
Twenty-seven spices were examined in this study, as detailed in [Table 1]. All spices were purchased from retail markets in the UAE, namely at Al Ain and Dubai, between July 2016 and July 2017. Spices were individually collected in sealed plastic food bags and were transported to the laboratory for microbiological examination at ambient temperature.
M. abscessus isolates (n = 10) were obtained from the HSC Microbiology Culture Repository, MicroARK (www.microark.com), housed at the Northern Ireland Public Health Laboratory, at Belfast City Hospital. These isolates consisted of nine clinical isolates obtained from patients with CF and one Reference Strain (Mycobacterium abscessus National Culture Type Collection [NCTC] 13031) obtained from the Public Health England (Colindale, London, UK). All isolates had been historically stored on slopes of Lowenstein-Jensen medium in glass universal containers at ambient temperature. All isolates were recovered and passaged twice on Columbia agar base (Oxoid CM0331; Oxoid Ltd., Basingstoke, UK) supplemented with 5% (v/v) defibrinated horse blood, which was incubated at 37°C for 5 days, before employment in the current study. A fresh culture of each isolate was prepared as described above and was harvested into 0.1% (w/v) peptone saline (CM0733) to yield a 0.5McFarland inoculation standard, for subsequent experiments.
Development of Spice Agar Medium
Spices (n = 27) were employed in this experiment, as detailed in [Table 1]. Approximately 0.2 g of each spice was weighed and added to 30 ml absolute ethanol (Sigma Aldrich Ltd., UK) and allowed to infuse overnight at room temperature. Following this, the absolute ethanol containing the combined spices was added to 1 L of Mueller Hinton agar (MHA) (CM0337) and was sterilized by autoclaving, prior to the pouring of MHA plates containing circa 0.02% (w/v) of each spice, to produce Spice Agar Medium (SAM). Unsupplemented MHA plates were also prepared as controls.
Growth of Mycobacterium abscessus isolates on Spice Agar Medium
M. abscessus isolates, as detailed above, were inoculated on SAM plates, as well as onto unsupplemented MHA plates (control) and were incubated as detailed above. The following culture parameters were examined as follows: (i) bacterial colony growth and proliferation, (ii) inhibitory effect of SAM medium, (iii) pigment production, and (iv) smooth to rough colonial conversion.
Interference with antibiotic susceptibility
An experiment was designed to investigate the effect of spices on antibiotic susceptibility on M. abscessus isolates, as detailed above. Bacteria were prepared and inoculated (McFarland 0.5 standard) onto (i) SAM medium and (ii) unsupplemented MHA medium. Two antibiotics were added to plates on standard antibiotic disks, which included amikacin (30 μg) and linezolid (10 μg). Inoculated plates were incubated for 5d at 37°C, before reading, where the zone of inhibition was recorded (mm). Mean antibiotic susceptibility, expressed as zone sizes (mm), were calculated for each of the two antibiotics tested. Paired t-test was calculated for each antibiotic, where the null hypothesis was that there was no significant difference in antibiotic susceptibility zone sizes, with and without spices. P < 0.05 (5%) was considered statistically significant.
| Results and Discussion|| |
Five isolates of M. abscessus (5/10; 50%) failed to grow on the spice enriched medium, which included four clinical isolates and the NCTC Reference Strain. Of the remaining five isolates which grew on the spice medium, no cultural phenotypic differences were observed, compared to unsupplemented controls.
The effect of spices on antibiotic susceptibility with the five isolates that grew on SAM is shown in [Figure 1]. In the case of both amikacin and linezolid, the zone of inhibition increased with the inclusion of the spices. Initially, all isolates of M. abscessus were fully resistant to linezolid (mean zone of inhibition = 0 mm), and growth was to the edge of the antibiotic disk, whereas when in the presence of spices, large zones of inhibition were observed (mean zone of inhibition = 33.3 mm). With amikacin, the mean zone of inhibition increased from 23.2 mm to 32.0 mm, in the presence of spices. These data suggest that the spices were interacting synergistically with the antibiotic, thus making the antibiotic more potent against the bacteria tested. In both cases, this increase in antibiotic was statistically significant [Figure 1].
|Figure 1: Effect of the presence of 27 spices (0.02% [w/v]; 200 ppm) on antibiotic susceptibility of Mycobacterium abscessus to amikacin and linezolid|
Click here to view
The most significant finding of the current study was the interaction between spices and antibiotic susceptibility with M. abscessus. Antimicrobial resistance (AMR) has become a global public health problem which now attracts the attention of major political bodies, including the G7 nations. AMR is particularly problematic in several countries in South Asia, including India, Pakistan, Bangladesh, and Sri Lanka, countries which are major spice producers and consumers/users. The current in vitro study showed that in the presence of a combination of 27 spices at low concentration (circa. 0.02% [w/v]; 200 ppm), antibiotic susceptibility increased with two major antibiotics, commonly used to treat NTM infection in patients with CF, namely amikacin (aminoglycoside) and linezolid (oxazolidone). Our studies demonstrated that the spices did not directly inhibit the growth of all the M. abscessus, but were able to interact synergistically with the two antibiotics tested. At this stage, we do not have any evidence to indicate that this also occurs in the in vivo scenario in humans, but given the escalating problems associated with global AMR; this finding is of interest and warrants further investigation.
The consequences of such synergistic behaviour with the antibiotics are several folds, including (i) the lowering of minimum inhibitory concentrations of established pathogens against conventional antibiotics, effecting slowing down or indeed reversing the effects of antibiotic resistance development and (ii) reducing the need for employment of expensive new antibiotics and supporting the proper use of existing generic antibiotics, which are both widely available and cheap.
| Conclusion|| |
This study is significant as it demonstrates a positive interaction between spices and the conventional antimycobacterial antibiotics, amikacin, and linezolid. Given the burden of AMR to M. abscessus, particularly in a patient with chronic disease such as CF, any food-related innovation that can help maximize the potency of existing antimycobacterial antibiotics is to be encouraged and developed. The specific mechanism as to how spices increase the potency of such antibiotics needs to be elucidated, as well as novel food (spice) delivery modalities, developed, including novel medicinal foodstuffs or functional foods, that can harness this beneficial effect in vivo to medicine and society.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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