Reservoirs of antimicrobial resistance in the context of One Health

The emergence and spread of antimicrobial resistance (AMR) and resistant bacteria, are a global public health challenge. Through horizontal gene transfer, potential pathogens can acquire antimicrobial resistance genes (ARGs) that can subsequently be spread between human, animal, and environmental reservoirs. To understand the dissemination of ARGs and linked microbial taxa, it is necessary to map the resistome within different microbial reservoirs. By integrating knowledge on ARGs in the different reservoirs, the One Health approach is crucial to our understanding of the complex mechanisms and epidemiology of AMR. Here, we highlight the latest insights into the emergence and spread of AMR from the One Health perspective, providing a baseline of understanding for future scientific investigations into this constantly growing global health threat.

Altered infective competence of the human gut microbiome in COVID-19

BACKGROUND

Infections with SARS-CoV-2 have a pronounced impact on the gastrointestinal tract and its resident microbiome. Clear differences between severe cases of infection and healthy individuals have been reported, including the loss of commensal taxa. We aimed to understand if microbiome alterations including functional shifts are unique to severe cases or a common effect of COVID-19. We used high-resolution systematic multi-omic analyses to profile the gut microbiome in asymptomatic-to-moderate COVID-19 individuals compared to a control group.

RESULTS

We found a striking increase in the overall abundance and expression of both virulence factors and antimicrobial resistance genes in COVID-19. Importantly, these genes are encoded and expressed by commensal taxa from families such as Acidaminococcaceae and Erysipelatoclostridiaceae, which we found to be enriched in COVID-19-positive individuals. We also found an enrichment in the expression of a betaherpesvirus and rotavirus C genes in COVID-19-positive individuals compared to healthy controls.

CONCLUSIONS

Our analyses identified an altered and increased infective competence of the gut microbiome in COVID-19 patients. Video Abstract.

Association of tumor necrosis factor-α (G-308A) genetic variant with matrix metalloproteinase-9 activity and joint destruction in early rheumatoid arthritis

Matrix metalloproteinases (MMPs) are the key enzymes responsible for the joint destruction. Their activity is regulated by the level of proinflammatory cytokines. The aim of this study was to examine the impact of TNF-α G-308A polymorphism on MMP-9 levels in blood plasma (BP) and synovial fluid (SF) of patients with rheumatoid arthritis (RA) and their role in progression of joint destruction. One hundred thirty-four subjects were enrolled in this study. TNF-α G-308A polymorphism was determined using PCR-RFLP method. ELISA assay was used for the detection of MMP-9 activity in BP and SF. Joint damage was estimated by hands and feet radiography. Larsen score and annual changes in LS were used for quantitative evaluation of joint destruction and radiographic progression of disease. MMP-9 activity in BP and SF was significantly higher in RA compared to controls, as well as in SF of patients with erosive compared to nonerosive RA. Faster radiographic progression and increased MMP-9 activity in BP and SF were detected in the group A (GA or AA genotype carriers) compared to the group G (GG genotype carriers). However, statistical significance was revealed only for MMP-9 activity in SF (p < 0.05). MMP-9 activity in BP and SF is significantly higher in RA patients compared to patients with osteoarthritis. The presence of TNF-α-308A allele is associated with increased MMP-9 activity in SF of patients with early RA and may be a predictor of rapid radiographic progression of disease.

Vitamin D Receptor Gene Polymorphisms in Serbian Patients With Bronchial Asthma: A Case-Control Study

Vitamin D and single nucleotide polymorphisms (SNPs) in vitamin D receptor (VDR) gene are potentially involved in the pathogenesis of bronchial asthma (BA); however, precise mechanisms by which vitamin D reduces the inflammation and the role of VDR SNPs in BA are not completely understood. The aim of this study was to examine the possible associations of FokI, BsmI, ApaI, and TaqI SNPs with BA. A total of 168 subjects were screened for VDR SNPs using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) method. The obtained results showed statistically significant differences in the distribution of FokI genotypes (df = 2; P = 0.008) and alleles (P = 0.002; OR = 0.446; 95%CI = 0.264-0.752) between patients and controls. Distributions of BsmI, ApaI, and TaqI genotypes and alleles did not show statistical differences. BsmI, ApaI, and TaqI SNPs are in linkage disequilibrium (LD) in the whole studied group, as well as in BA patients and controls. The strongest LD was observed between BsmI and TaqI (r²  = 0.69 for all subjects in the study; r²  = 0.75 in BA; r²  = 0.64 in controls), while lower values of LD were observed for BsmI and ApaI, and ApaI and TaqI SNPs. This is the first study that examined the association of VDR SNPs (FokI, BsmI, ApaI, and TaqI) in Serbian patients with BA indicating protective effect of FF genotype and F allele of FokI SNP on BA development. J. Cell. Biochem. 118: 3986-3992, 2017. © 2017 Wiley Periodicals, Inc.

The effect of melatonin on the liver of rats exposed to microwave radiation

OBJECTIVES

We aimed to clarify if melatonin treatment (2 mg/kg i.p.) may favorably impact the liver tissue in rats exposed to microwave radiation. The experiment was performed on 84 six-weeks-old Wistar male rats exposed for 4h a day, for 20, 40 and 60 days, respectively, to microwaves (900 MHz, 100-300 microT, 54-160 V/m). Rats were divided in to four groups: I (control) - rats treated with saline, II (Mel) - rats treated with melatonin, III (MWs) - microwave exposed rats, IV (MWs + Mel) - MWs exposed rats treated with melatonin. We evaluated oxidative stress parameters (malondialdehyde and carbonyl group content), catalase, xanthine oxidase, deoxyribonuclease I and II activity.

BACKGROUND

Oxidative stress is the key mechanism of the microwave induced tissue injury. Melatonin, a lipophilic indoleamine primarily synthesized and released from the pineal gland is a powerful antioxidant.

RESULTS

Exposure to microwaves caused an increase in malondialdehyde after 40 (p < 0.01), protein carbonyl content after 20 (p < 0.05), catalase (p < 0.05) and xantine oxidase activity (p < 0.05) after 40 days. Increase in deoxyribonuclease I activity was observed after 60 days (p < 0.05), while deoxyribonuclease II activity was unaffected. Melatonin treatment led to malondialdehyde decrease after 40 days (p< 0.05), but surprisingly had no effect on other analyzed parameters.

CONCLUSION

Melatonin exerts certain antioxidant effects in the liver of rats exposed to microwaves, by diminishing the intensity of lipid peroxidation(Fig. 6, Ref. 32).

The Effects of Melatonin on Oxidative Stress Parameters and DNA Fragmentation in Testicular Tissue of Rats Exposed to Microwave Radiation

BACKGROUND

Microwaves from mobile phones are one of the environmental toxicants that are capable of compromising male fertility by inducing oxidative stress and apoptosis in the testes. Melatonin is a lipophilic tryptophan indole amine and a potent antioxidant.

OBJECTIVES

The aim of the study was to evaluate the effect of melatonin treatment on oxidative stress parameters and DNA fragmentation in the testicular tissue of rats exposed to microwave radiation (4 h/day).

MATERIAL AND METHODS

Adult Wistar rats were divided in 4 groups: I--treated with saline; II--treated with melatonin; III--exposed to microwaves; IV--exposed to microwaves and treated with melatonin. The melatonin (2 mg/kg ip) was administered daily. The animals were sacrificed after 20, 40 and 60 days.

RESULTS

Melatonin treatment prevented previously registered increases in malondialdehyde after only 20 days. Furthermore, it reversed the effects of microwave exposure on xanthine oxidase (after 40 days) and acid-DNase activity (after 20 days). However, neither protein carbonyl content nor catalase and alkaline Dnase activity were changed due to melatonin treatment.

CONCLUSIONS

Melatonin exerts potent antioxidant effects in the testes of rats exposed to microwaves by decreasing the intensity of oxidative stress; it also reduces DNA fragmentation.

Gene polymorphisms of tumor necrosis factor alpha and antioxidant enzymes in bronchial asthma

BACKGROUND

Bronchial asthma is an inflammatory disease resulting from a combination of genetic and environmental factors. Single nucleotide polymorphisms in the regulatory regions of cytokine and antioxidant enzyme genes may affect cytokine production and enzyme activity, and thus play a contributory role in asthma pathogenesis.

OBJECTIVES

The aim of this study was to examine the association of manganese superoxide dismutase (MnSOD) Ala16Val, catalase (CAT) A-21T and tumor necrosis factor alpha (TNF-α) G-308A polymorphisms with bronchial asthma.

MATERIAL AND METHODS

A total of 79 patients with asthma and 95 healthy controls were screened for MnSOD Ala16Val, CAT A-21T and TNF-α G-308A polymorphisms using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

The results obtained showed significantly higher prevalence of the MnSOD ValVal genotype (χ2=14.463, df=2, p=0.001) and MnSOD 16Val allele (χ2=12.862, p=0.026, OR=0.451, 95% CI=0.291-0.699) in patients with asthma compared to controls. The genotype and allele frequencies distribution of CAT A-21T and TNF-α G-308A gene polymorphisms did not show differences between patients and controls.

CONCLUSIONS

Our results show an association of MnSOD Ala16Val genetic polymorphism with asthma in a Serbian population and suggest a protective role of the MnSOD 16Ala allele.