Musculoskeletal complications of fluoroquinolones: guidelines and precautions for usage in the athletic population

Fluoroquinolone-Mediated Tendinopathy and Tendon Rupture

The fluoroquinolone (FQ) class of antibiotics includes the world's most prescribed antibiotics such as ciprofloxacin, levofloxacin, and ofloxacin that are known for their low bacterial resistance. This is despite their potential to trigger severe side effects, such as myopathy, hearing loss, tendinopathy, and tendon rupture. Thus, healthcare organizations around the world have recommended limiting the prescription of FQs. Tendinopathy is a common name for maladies that cause pain and degeneration in the tendon tissue, which can result in tendon rupture. Whilst there are several identified effects of FQ on tendons, the exact molecular mechanisms behind FQ-mediated tendon rupture are unclear. Previous research studies indicated that FQ-mediated tendinopathy and tendon rupture can be induced by changes in gene expression, metabolism, and function of tendon resident cells, thus leading to alterations in the extracellular matrix. Hence, this review begins with an update on FQs, their mode of action, and their known side effects, as well as summary information on tendon tissue structure and cellular content. Next, how FQs affect the tendon tissue and trigger tendinopathy and tendon rupture is explored in detail. Lastly, possible preventative measures and promising areas for future research are also discussed. Specifically, follow-up studies should focus on understanding the FQ-mediated tendon changes in a more complex manner and integrating in vitro with in vivo models. With respect to in vitro systems, the field should move towards three-dimensional models that reflect the cellular diversity found in the tissue.

An In Vitro Investigation of Levofloxacin-Induced Cytotoxicity in Rat Bone Marrow Mesenchymal Stem Cells

BACKGROUND

Levofloxacin, a widely used fluoroquinolone antibiotic, has been linked to musculoskeletal complications. However, its impact on bone marrow mesenchymal stem cells (BMSCs), which are vital for tissue repair and regeneration, remains poorly understood.

AIM

This study aims to examine the impact on rat BMSCs following therapy with levofloxacin.

METHODS

 Rat BMSCs were exposed to various doses of levofloxacin (0, 14, 28, 56, 112, and 224 μM) to assess its possible cytotoxic impact on these stem cells. Cell viability was assessed using the MTT assay to evaluate the cytotoxic effects of levofloxacin. Cell apoptosis was calculated with Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) double staining, along with the expression levels of matrix metalloproteinase-3 (MMP-3), MMP-13, collagen type I alpha 1 (Col1A1), tissue inhibitor of metalloproteinase-1 (TIMP-1), and TIMP-3 messenger RNA (mRNA), which were assessed using RT-PCR. An apoptotic marker, caspase-3, was detected by immunocytochemical analysis.

RESULTS

 In certain concentrations (0-224 μM), as the concentration of levofloxacin increased, the number of apoptotic cells increased. The results demonstrated that levofloxacin significantly upregulated the mRNA levels of MMP-3 as well as MMP-13 in a dose-related manner, simultaneously downregulating TIMP-1 expression. In contrast, the expression of TIMP-3 and Col1A1 remained unaffected. In addition, the expression of caspase-3 was substantially elevated by levofloxacin in a concentration-related manner, between 28 μM and 224 μM, as indicated by immunocytochemistry.

CONCLUSION

 These findings provide evidence that levofloxacin exerts cytotoxicity on BMSCs, shown by increased apoptosis and a reduction in extracellular matrix components, highlighting a potential adverse impact of levofloxacin. Additionally, this cytotoxic effect may negatively affect fracture healing and impair the regenerative capacity of BMSCs.

Fluoroquinolones tackling antimicrobial resistance: Rational design, mechanistic insights and comparative analysis of norfloxacin vs ciprofloxacin derivatives

Antimicrobial resistance poses a global health concern and develops a need to discover novel antimicrobial agents or targets to tackle this problem. Fluoroquinolone (FN), a DNA gyrase and topoisomerase IV inhibitor, has helped to conquer antimicrobial resistance as it provides flexibility to researchers to rationally modify its structure to increase potency and efficacy. This review provides insights into the rational modification of FNs, the causes of resistance to FNs, and the mechanism of action of FNs. Herein, we have explored the latest advancements in antimicrobial activities of FN analogues and the effect of various substitutions with a focus on utilizing the FN nucleus to search for novel potential antimicrobial candidates. Moreover, this review also provides a comparative analysis of two widely prescribed FNs that are ciprofloxacin and norfloxacin, explaining their rationale for their design, structure-activity relationships (SAR), causes of resistance, and mechanistic studies. These insights will prove advantageous for new researchers by aiding them in designing novel and effective FN-based compounds to combat antimicrobial resistance.

Electrospun Aligned Nanofiber Yarns Constructed Biomimetic M-Type Interface Integrated into Precise Co-Culture System as Muscle-Tendon Junction-on-a-Chip for Drug Development

The incorporation of engineered muscle-tendon junction (MTJ) with organ-on-a-chip technology provides promising in vitro models for the understanding of cell-cell interaction at the interface between muscle and tendon tissues. However, developing engineered MTJ tissue with biomimetic anatomical interface structure remains challenging, and the precise co-culture of engineered interface tissue is further regarded as a remarkable obstacle. Herein, an interwoven waving approach is presented to develop engineered MTJ tissue with a biomimetic "M-type" interface structure, and further integrated into a precise co-culture microfluidic device for functional MTJ-on-a-chip fabrication. These multiscale MTJ scaffolds based on electrospun nanofiber yarns enabled 3D cellular alignment and differentiation, and the "M-type" structure led to cellular organization and interaction at the interface zone. Crucially, a compartmentalized co-culture system is integrated into an MTJ-on-a-chip device for the precise co-culture of muscle and tendon zones using their medium at the same time. Such an MTJ-on-a-chip device is further served for drug-associated MTJ toxic or protective efficacy investigations. These results highlight that these interwoven nanofibrous scaffolds with biomimetic "M-type" interface are beneficial for engineered MTJ tissue development, and MTJ-on-a-chip with precise co-culture system indicated their promising potential as in vitro musculoskeletal models for drug development and biological mechanism studies.

Anti-Microbial Drug Metronidazole Promotes Fracture Healing: Enhancement in the Bone Regenerative Efficacy of the Drug by a Biodegradable Sustained-Release In Situ Gel Formulation

Nitroimidazoles comprise a class of broad-spectrum anti-microbial drugs with efficacy against parasites, mycobacteria, and anaerobic Gram-positive and Gram-negative bacteria. Among these drugs, metronidazole (MTZ) is commonly used with other antibiotics to prevent infection in open fractures. However, the effect of MTZ on bone remains understudied. In this paper, we evaluated six nitroimidazole drugs for their impact on osteoblast differentiation and identified MTZ as having the highest osteogenic effect. MTZ enhanced bone regeneration at the femur osteotomy site in osteopenic ovariectomized (OVX) rats at the human equivalent dose. Moreover, in OVX rats, MTZ significantly improved bone mass and strength and improved microarchitecture compared to the vehicle-treated rats, which was likely achieved by an osteogenic mechanism attributed to the stimulation of the Wnt pathway in osteoblasts. To mitigate the reported neurological and genotoxic effects of MTZ, we designed an injectable sustained-release in situ gel formulation of the drug that improved fracture healing efficacy by 3.5-fold compared to oral administration. This enhanced potency was achieved through a significant increase in the circulating half-life and bioavailability of MTZ. We conclude that MTZ exhibits osteogenic effects, further accentuated by our sustained-release delivery system, which holds promise for enhancing bone regeneration in open fractures.

Prevalence, risk factors and treatment outcomes of fluoroquinolones-associated tendinopathy in tuberculosis patients at university hospital, Thailand

Background

Tuberculosis (TB) is an epidemic disease in Thailand. Fluoroquinolones are used to treat TB and have a lengthy treatment course. Therefore, many patients may have adverse effects from these medications. Tendinopathy has been reported as a significant adverse effect of fluoroquinolones. Although the mechanism of tendinopathy from fluoroquinolones is not fully understood, it can progress to a more serious consequence such as a ruptured tendon which can result in morbidity if not treated effectively.

Methods

This study was a single-centered, retrospective descriptive study conducted in patients at a tertiary-level university hospital in Thailand. TB patients who received fluoroquinolones for the treatment of TB from January 2017 to December 2019 were enrolled. This study assessed the prevalence, clinical characteristics, treatment, treatment outcomes for fluoroquinolones-associated tendinopathy, and treatment outcomes of TB.

Results

During the study period, 184 participants that were diagnosed with TB and used fluoroquinolones were enrolled in the study. 34 (18.5%) participants developed tendinopathy. The risk factors that were associated with fluoroquinolones-associated tendinopathy were younger age (<60 years) (Odd ratio (OR) 3.61; 95% CI 1.16-11.23), female (OR 3.54; 95% CI 1.58-7.90), and prolonged usage of levofloxacin (>180 days) (OR 2.61; 95%CI 1.12-6.08). All participants who developed tendinopathy received conservative treatment; the dose of fluoroquinolones was reduced in 9 (26.4%) participants, fluoroquinolones were discontinued in 7 (20.6%) participants and the rest of the participants (n = 18; 52.9%) had conservative treatment. After conservative treatment, 25 (73.5%) participants recovered from tendinopathy. For the TB treatment, 27 (79.4%) participants in the tendinopathy group completed TB treatment and none of them experienced treatment failure. On the other hand, 89 (59.3%) participants in the no tendinopathy group had completed their TB treatment and 3 (2%) of them experienced treatment failure.

Conclusions

The prevalence of fluoroquinolones-associated tendinopathy was not uncommon, and the risk of fluoroquinolones-associated tendinopathy was high in young and female patients. Levofloxacin use was related to an elevated risk of developing tendinopathy, which was dose- and duration-dependent. Conservative treatment, reducing the dose or discontinuation of fluoroquinolones successfully improved the symptoms of tendinopathy. Fluoroquinolones-associated tendinopathy did not affect the treatment of TB.

Urinary antibiotic exposure and low grip strength risk in community-dwelling elderly Chinese by gender and age

Emerging studies have shown that environmental contaminants were related to decreased handgrip strength. Nevertheless, no prior research has investigated the relationship of exposure to environmental antibiotics with grip strength. Thus, we explored the relationship between urinary antibiotic burden and grip strength among the elderly in China. This study consisted of 451 men and 539 women from the baseline survey of a cohort study. Commonly used antibiotics for humans and animals were detected in 990 urine samples through a biomonitoring method. Grip strength was measured by an electronic dynamometer. We examined the associations of antibiotic exposure with low grip strength (LGS), grip strength, and grip strength index, respectively. Results suggested that 34.9% of participants developed LGS, and 93.0% of individuals were exposed to 1-10 antibiotics. Among women, oxytetracycline (Quartile 2: odds ratio: 2.97, 95% confidence interval: 1.36-6.50), florfenicol (Quartile 3: 2.60 [1.28-5.27]), fluoroquinolones (Quartile 4: 1.88 [1.07-3.30]), and chloramphenicols (Quartile 3: 2.73 [1.35-5.51]) could enhance LGS risk. Among men, ofloxacin (Quartile 2: 3.32 [1.45-7.59]) increased LGS risk, whereas tetracycline (Quartile 2: 0.31 [0.11-0.88]) was implicated in reduced LGS risk. In participants < 70 years, ofloxacin (Quartile 2: 3.00 [1.40-6.42]) could increase LGS risk. For participants who were 70 years of age or older, veterinary antibiotics (Quartile 3: 1.73 [1.02-2.94]) were linked to a 73% increased risk of LGS. Our findings suggested that antibiotics mainly pertained to LGS, and there were gender and age disparities in associations between antibiotic exposure and muscle strength indicators in the elderly Chinese population.

Achilles Tendon Injuries Requiring Surgical Treatment in the Pediatric and Adolescent Population: A Case Series

ABSTRACT

Pediatric Achilles tendon injuries requiring surgical treatment are considered rare and have not been well described. A retrospective chart review was conducted from 2010 to 2020 to identify cases of acute Achilles tendon rupture or laceration that required surgical repair in individuals 19 years or younger. A total of 24 individuals with acute Achilles tendon ruptures (n = 8) and lacerations (n = 16) were identified. All spontaneous ruptures occurred in skeletally mature individuals during sports. One subject was on minocycline at the time of injury, while two had a body mass index (BMI) ≥ 99% for age. Another had a history of clubfoot surgery on the injured side. Patients with lacerations were younger (9.9 ± 3.3 vs 16.3 ± 1.6 years) and had lower BMI (17.3 ± 3.8 vs. 28.0 ± 9.4) than those with spontaneous ruptures. The majority of cases had good outcomes with no postoperative complications.

Antibiotic Therapy and Athletes: Is the Mitochondrial Dysfunction the Real Achilles’ Heel?

It is widely recognized that athletes consume oral antibiotics almost twice as often as observed in the non-sports population in order to reduce as much as possible the period of inactivity due to bacterial diseases. However, increasing evidences have demonstrated the ability of some classes of antibiotics to induce muscle weakness, pain, and a feeling of fatigue upon resuming physical activity conditions that considerably limit the athletic performance of athletes, ascribable to alterations in the biochemical mechanisms underlying normal musculoskeletal activity, such as mitochondrial respiration. For this reason, tailoring a treatment plan for effective antibiotics that limit an athlete’s risk is paramount to their safety and ability to maintain adequate athletic performance. The present review illustrates and critically analyzes the evidence on the use of antibiotics in sports, deepening the molecular mechanisms underlying the onset and development of muscle–tendon alterations in athletes as well as delineating the pharmacological strategies aimed at counteracting such adverse events.

Systemic quinolones and risk of retinal detachment III: a nested case-control study using a US electronic health records database

Background

Quinolones are popular antibiotics that are known for their potency, broad coverage, and reasonable safety. Concerns have been raised about a possible association between quinolones and retinal detachment (RD).

Methods

We conducted a nested case–control study using electronic health records (EHR) from the Health Facts® Database. The initial cohort included all patients who were admitted between 2000 and 2016, with no history of eye disease, and had a minimum medical history of one year. Eligible cases comprised inpatients who were first admitted with a primary diagnosis of RD between 2010 and 2015. Each eligible case was matched without replacement to five unique controls by sex, race, age, and period-at-risk. We used conditional logistic regression to calculate RD risk, adjusting for exposure to other medications, and major risk factors.

Results

We identified 772 cases and 3860 controls. Whereas our primary analysis of all subjects revealed no quinolone-associated RD risk, elevated but non-significant risks were noted in African Americans (ciprofloxacin and levofloxacin), those aged 56–70 years old (moxifloxacin), and women (ciprofloxacin).

Conclusion

Our study did not identify an elevated RD risk within 30 days following systemic administration of quinolone antibiotics. Suggestions of increased risk observed in some population subgroups warrant further investigation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00228-021-03260-4.

Toxicity induced by ciprofloxacin and enrofloxacin: oxidative stress and metabolism

Ciprofloxacin (CIP) (human use) and enrofloxacin (ENR) (veterinary use) are synthetic anti-infectious medications that belong to the second generation of fluoroquinolones. They have a wide antimicrobial spectrum and strong bactericidal effects at very low concentrations via enzymatic inhibition of DNA gyrase and topoisomerase IV, which are required for DNA replication. They also have high bioavailability, rapid absorption with favorable pharmacokinetics and excellent tissue penetration, including cerebral spinal fluid. These features have made them the most applied antibiotics in both human and veterinary medicine. ENR is marketed exclusively for animal medicine and has been widely used as a therapeutic veterinary antibiotic, resulting in its residue in edible tissues and aquatic environments, as well as the development of resistance and toxicity. Estimation of the risks to humans due to antimicrobial resistance produced by CIP and ENR is important and of great interest. Moreover, in rare cases due to their overdose and/or prolonged administration, the development of CIP and ENR toxicity may occur. The toxicity of these fluoroquinolones antimicrobials is mainly related to reactive oxygen species (ROS) and oxidative stress (OS) generation, besides metabolism-related toxicity. Therefore, CIP is restricted in pregnant and lactating women, pediatrics and elderly similarly ENR do in the veterinary field. This review manuscript aims to identify the toxicity induced by ROS and OS as a common sequel of CIP and ENR. Furthermore, their metabolism and the role of metabolizing enzymes were reported.

Francisella tularensis caused cervical lymphadenopathy in little children after a tick bite: Two case reports and a short literature review

Although Francisella (F.) tularensis is a well-described and understood zoonotic pathogen, its importance in Central Europe is relatively minor and, as such, tularaemia may be missed in the differential diagnosis. The annual incidence of tularaemia in the Czech Republic is relatively stable with up to 100 reported cases per year, except in the epidemic years 1998 and 1999 with 225 and 222 reported cases, respectively. It is, however, higher in comparison with the neighbouring countries. The common route of transmission in Central Europe is handling infected animals. Tularaemia is not commonly recognized as a tick-borne disease. Here we report two rare cases of a tick bite-associated ulceroglandular form of tularaemia in 2.5-year-old and 6.5-year-old children presenting with cervical lymphadenopathy. The unusual and interesting features of those cases are the young age and relatively uncommon route of transmission suggesting possible changes in the epidemiology of tularaemia in the Czech Republic. Therefore, the infection with F. tularensis should be considered in the differential diagnosis after a tick bite even in infants.

MRGPRX2 and Adverse Drug Reactions

Many adverse reactions to therapeutic drugs appear to be allergic in nature, and are thought to be triggered by patient-specific Immunoglobulin E (IgE) antibodies that recognize the drug molecules and form complexes with them that activate mast cells. However, in recent years another mechanism has been proposed, in which some drugs closely associated with allergic-type events can bypass the antibody-mediated pathway and trigger mast cell degranulation directly by activating a mast cell-specific receptor called Mas-related G protein-coupled receptor X2 (MRGPRX2). This would result in symptoms similar to IgE-mediated events, but would not require immune priming. This review will cover the frequency, severity, and dose-responsiveness of allergic-type events for several drugs shown to have MRGPRX2 agonist activity. Surprisingly, the analysis shows that mild-to-moderate events are far more common than currently appreciated. A comparison with plasma drug levels suggests that MRGPRX2 mediates many of these mild-to-moderate events. For some of these drugs, then, MRGPRX2 activation may be considered a regular and predictable feature after administration of high doses.

Dermatomyositis Developed After Exposure to Epstein-Barr Virus Infection and Antibiotics Use

Dermatomyositis is an inflammatory disorder involving muscle and skin. Similar to many other autoimmune diseases, environmental factors appear to trigger the onset of disease in some cases. Many drugs have been reported to be associated with dermatomyositis, and rarely infections have been described as potential triggering agents. Here we are describing a case of dermatomyositis that developed after doxycycline and levofloxacin use, who also had recent Epstein-Barr virus infection. Dermatomyositis associated with doxycycline or levofloxacin use has not yet been described in the literature, while reports of dermatomyositis after Epstein-Barr virus infection have been rare and limited to juvenile dermatomyositis or in association with cancer. It is important for clinicians to be aware of this rare association so that the diagnosis and treatment can be exercised promptly.

A New Antibiotic-Loaded Sol-Gel Can Prevent Bacterial Prosthetic Joint Infection: From in vitro Studies to an in vivo Model

The aim of this study was to evaluate the effect of a moxifloxacin-loaded organic-inorganic sol-gel with different antibiotic concentration in the in vitro biofilm development and treatment against Staphylococcus aureus, S. epidermidis, and Escherichia coli, cytotoxicity and cell proliferation of MC3T3-E1 osteoblasts; and its efficacy in preventing the prosthetic joint infection (PJI) caused by clinical strains of S. aureus and E. coli using an in vivo murine model. Three bacterial strains, S. epidermidis ATCC 35984, S. aureus 15981, and, E. coli ATCC 25922, were used for microbiological studies. Biofilm formation was induced using tryptic-soy supplemented with glucose for 24 h, and then, adhered and planktonic bacteria were estimated using drop plate method and absorbance, respectively. A 24-h-mature biofilm of each species growth in a 96-well plate was treated for 24 h using a MBECTM biofilm Incubator lid with pegs coated with the different types of sol-gel, after incubation, biofilm viability was estimated using alamrBlue. MC3T3-E1 cellular cytotoxicity and proliferation were evaluated using CytoTox 96 Non-Radioactive Cytotoxicity Assay and alamarBlue, respectively. The microbiological studies showed that sol-gel coatings inhibited the biofilm development and treated to a mature biofilm of three evaluated bacterial species. The cell studies showed that the sol-gel both with and without moxifloxacin were non-cytotoxic and that cell proliferation was inversely proportional to the antibiotic concentration containing by sol-gel. In the in vivo study, mice weight increased over time, except in the E. coli-infected group without coating. The most frequent symptoms associated with infection were limping and piloerection; these symptoms were more frequent in infected groups with non-coated implants than infected groups with coated implants. The response of moxifloxacin-loaded sol-gel to infection was either total or completely absent. No differences in bone mineral density were observed between groups with coated and non-coated implants and macrophage presence lightly increased in the bone grown directly in contact with the antibiotic-loaded sol-gel. In conclusion, moxifloxacin-loaded sol-gel coating is capable of preventing PJI caused by both Gram-positive and Gram-negative species.

High Incidence of New-Onset Joint Pain in Patients on Fluoroquinolones as Antituberculous Treatment

BACKGROUND

Joint pain is frequently observed in patients on antituberculous treatment, and pyrazinamide is known to be associated with joint pain in patients receiving antituberculous treatment. Fluoroquinolone-associated joint pain and tendon injury have been reported in long-term corticosteroid and transplant recipients, but data are lacking in patients with tuberculosis.

OBJECTIVES

The objective of this study was to examine the incidence of joint pain manifested during administration of antituberculous therapy and their association with fluoroquinolones.

METHODS

Patients diagnosed with tuberculosis attending the outpatient clinic over a period of 1 year were reviewed and divided into 3 groups: group A receiving pyrazinamide, group B receiving a fluoroquinolone, and group C receiving both pyrazinamide and a fluoroquinolone. Latency to onset of joint pain was noted in all 3 groups. Joint pain was initially managed with analgesics, and associated hyperuricemia was treated with allopurinol/febuxostat. Causative drugs were stopped in case of intolerable joint pain.

RESULTS

260 patients (47% females, aged 38 ± 18 years; mean ± SD) were included [group A (n = 140), group B (n = 81), and group C (n = 39)]. Overall, 76/260 (29%) patients developed joint pain: group A - 24/140 patients (17%), group B - 32/81 patients (40%), and group C - 20/39 patients (51%). The median latency to the onset of joint pain was 83 days (interquartile range, IQR 40-167): 55 days (IQR 32-66) in group A, 138 days (IQR 74-278) in group B, and 88 days (IQR 34-183) in group C. Hyperuricemia was present in 12/24 (50%) patients in group A and 11/20 (55%) patients in group C. Pyrazinamide was stopped in 7/140 (5%) patients in group A, fluoroquinolones in 6/81 (7%) patients in group B, and both pyrazinamide and fluoroquinolones were stopped in 5/39 (13%) patients in group C because of intolerable joint pain. Major joints affected were knees and ankles.

CONCLUSION

There is a high incidence of joint pain in patients receiving antituberculous treatment, which is higher when fluoroquinolones or the pyrazinamide-fluoroquinolone combination are administered as compared to pyrazinamide alone.

Biological and chemical changes in fluoroquinolone-associated tendinopathies: a systematic review

INTRODUCTION

The present systematic review investigates the biological and chemical mechanisms that affect the health and structure of tendons following the use of fluoroquinolones (FQs).

SOURCES OF DATA

A total of 12 articles were included, organized, and reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

AREAS OF AGREEMENT

Five mechanisms were identified: arrest of proliferation through a decreased activity of cyclin B, CDK-1, CHK-1, and increased PK-1; decrease tenocytes migration through decreased phosphorylation of FAK; decrease type I collagen metabolism through increased MMP-2; chelate effect on ions that influence epigenetics and several enzymes; fluoroquinolones-induced ROS (radical oxygen species) production in mitochondria.

AREAS OF CONTROVERSY

There is no definite structure-damage relationship. The dose-effect relationship is unclear.

GROWING POINTS

Knowing and defining the damage exerted by FQs plays a role in clinical practice, replacing FQs with other antibacterial drugs or using antioxidants to attenuate their pathological effects.

AREAS TIMELY FOR DEVELOPING RESEARCH

Clinical and basic sciences studies for each FQs are necessary.

Acute Achilles tendon rupture after treatment with levofloxacin in a patient with giant cell arteritis

The authors report a case of a 67-year-old woman with giant cell arteritis with acute Achilles tendon rupture, which occurred after 3 days of levofloxacin therapy introduced because of newly diagnosed erosive gastritis associated with Helicobacter pylori infection. The Achilles tendon rupture was surgically treated and the patient made a complete recovery. In view of the widespread use of levofloxacin in practice, this case report raises important clinical implications. Tendinopathies are a known complication, quite rare in the healthy population, but the risk of rupture significantly increases in the population of patients over 60 years of age, with chronic usage of glucocorticosteroids, impaired renal function and recipients of organ transplants. What needs underlining, there are also described differences between individual fluoroquinolones as a cause of tendon damage in this group. Considering the widespread use of this group of drugs in patients, knowledge about the risk of adverse events including tendinopathy promotes safe use of fluoroquinolones.

Seasonal Variation of Achilles Tendon Injury

Background:

Achilles tendon rupture (ATR) is a common injury with increasing incidence. Several risk factors have been identified; however, little is known about seasonal variations in injury prevalence. Previous reports have generated mixed results, with no clear consensus in the literature. The purpose of this investigation was to retrospectively review ATRs seen at a major academic orthopaedic surgery department in New York City to determine whether a statistically significant seasonal pattern of ATRs exists.

Methods:

A retrospective chart review was conducted, identifying patients with an acute ATR. Patients were excluded if they had a chronic rupture, laceration, débridement for tendinitis, Haglund deformity, or other nonacute indications for surgery. Date and mechanism of injury were determined from the clinical record.

Results:

The highest rate of injury was seen in spring (P = 0.015) and the lowest in fall (P < 0.001), both of which were statistically significant. Overall, no statistically significant difference was noted in summer or winter, although more injuries were seen in summer. When only sports-related injuries are considered, a similar trend is seen, with most injuries occurring in spring (n = 48, P = 0.076) and fewest in fall (n = 25, P = 0.012); however, only the lower number in fall reaches statistical significance. No statistically significant difference was noted between seasons when only non–sports-related injuries were considered.

Conclusion:

A statistically significant increase was noted in the incidence of ATRs in spring and a statistically significant decrease in fall. The need for recognition of risk factors and preventive education is increasingly important in the orthopaedic surgery community and for primary care physicians, athletic trainers, coaches, and athletes.

Level of Evidence:

Prognostic level IV

Norfloxacin salts of carboxylic acids curtail planktonic and biofilm mode of growth in ESKAPE pathogens

AIMS

To enhance the antimicrobial and antibiofilm activity of norfloxacin against the planktonic and biofilm mode of growth in ESKAPE pathogens using chemically modified norfloxacin salts.

METHODS AND RESULTS

Antimicrobial testing, synergy testing and time-kill curve analysis were performed to evaluate antibacterial effect of norfloxacin carboxylic acid salts against ESKAPE pathogens. In vivo efficacy to reduce bacterial bioburden was evaluated in zebrafish infection model. Crystal violet assay and live-dead staining were performed to discern antibiofilm effect. Membrane permeability, integrity and molecular docking studies were carried out to ascertain the mechanism of action. The carboxylic acid salts, relative to parent molecule norfloxacin, displayed two- to fourfold reduction in minimum inhibitory concentration against Staphylococcus aureus and Pseudomonas aeruginosa, in addition to displaying potent bacteriostatic effect against certain members of ESKAPE pathogens. In vivo treatments revealed that norfloxacin tartrate (SRIN2) reduced MRSA bioburden by greater than 1 log fold relative to parent molecule in the muscle tissue. In silico docking with gyrA of S. aureus showed increased affinity of SRIN2 towards DNA gyrase. The enhanced antibacterial effect of norfloxacin salts could be partially accounted by altered membrane permeability in S. aureus and perturbed membrane integrity in P. aeruginosa. Antibiofilm studies revealed that SRIN2 (norfloxacin tartrate) and SRIN3 (norfloxacin benzoate) exerted potent antibiofilm effect particularly against Gram-negative ESKAPE pathogens. The impaired colonization of both S. aureus and P. aeruginosa due to improved norfloxacin salts was further supported by live-dead imaging.

CONCLUSION

Norfloxacin carboxylic acid salts can act as potential alternatives in terms of drug resensitization and reuse.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our study shows that carboxylic acid salts of norfloxacin could be effectively employed to treat both planktonic- and biofilm-based infections caused by select members of ESKAPE pathogens.

Tendonitis and Tendinopathy: What Are They and How Do They Evolve?

The development of tendinitis and tendinopathy is often multifactorial and the result of both intrinsic and extrinsic factors. Intrinsic factors include anatomic factors, age-related factors, and systemic factors, whereas extrinsic factors include mechanical overload and improper form and equipment. Although tendinitis and tendinopathy are often incorrectly used interchangeably, they are in 2 distinct pathologies. Due to their chronicity and high prevalence in tendons about the ankle, including the Achilles tendon, the posterior tibialis tendon, and the peroneal tendons, tendinitis and tendinopathies cause significant morbidity and are important pathologies for physicians to recognize.

Serological Analysis and Drug Resistance of Chlamydia pneumoniae and Mycoplasma pneumoniae in 4500 Healthy Subjects in Shenzhen, China

Objective

To understand the prevalence and distribution of Chlamydia pneumoniae (CP) and Mycoplasma pneumoniae (MP) in the population and to provide a basis for the prevention and treatment of respiratory tract infection.

Methods

This study included a total of 4500 healthy subjects who were given physical examination in Shenzhen People's Hospital from January to December in 2016. Venous blood was drawn from people to detect the MP- and CP-specific IgG and IgM in the serum using chemiluminescence immunoassay (CLIA). The relationship of MP and CP infections with patient age, seasons, and percentage of infections was analyzed.

Conclusion

CP and MP cause high rate of asymptomatic infection, which may be associated with the high incidence of CP and MP infection, especially in children and the elderly population. Therefore, the implementation of effective and practical prevention measures has become an urgent need. MP culture and drug sensitivity test should be performed as early as possible in patients with manifested MP infections in order to ensure timely and proper treatment and to reduce the emergence of drug-resistant strains.

Safety Concerns Surrounding Quinolone Use in Children

Fluoroquinolones are highly effective antibiotics with many desirable pharmacokinetic and pharmacodynamic properties including high bioavailability, large volume of distribution, and a broad spectrum of antimicrobial activity. Despite their attractive profile as anti-infective agents, their use in children is limited, primarily due to safety concerns. In this review we highlight the pharmacological properties of fluoroquinolones and describe their current use in pediatrics. In addition, we provide a comprehensive assessment of the safety data associated with fluoroquinolone use in children. Although permanent or destructive arthropathy remains a significant concern, currently available data demonstrate that arthralgia and arthropathy are relatively uncommon in children and resolve following cessation of fluoroquinolone exposure without resulting in long-term sequelae. The concern for safety and risk of adverse events associated with pediatric fluoroquinolone use is likely driving the limited prescribing of this drug class in pediatrics. However, in adults, fluoroquinolones are the most commonly prescribed broad-spectrum antibiotics, resulting in the development of drug-resistant bacteria that can be challenging to treat effectively. The consequence of misuse and overuse of fluoroquinolones leading to drug resistance is a greater, but frequently overlooked, safety concern that applies to both children and adults and one that should be considered at the point of prescribing.

Fluoroquinolone-induced serious, persistent, multisymptom adverse effects

We present a case series of four previously healthy, employed adults without significant prior medical history in each of whom symptoms developed while on fluoroquinolones (FQs), with progression that continued following discontinuation evolving to a severe, disabling multisymptom profile variably involving tendinopathy, muscle weakness, peripheral neuropathy, autonomic dysfunction, sleep disorder, cognitive dysfunction and psychiatric disturbance. Physicians and patients should be alert to the potential for FQ-induced severe disabling multisymptom pathology that may persist and progress following FQ use. Known induction by FQs of delayed mitochondrial toxicity provides a compatible mechanism, with symptom profiles (and documented mechanisms of FQ toxicity) compatible with the hypothesis of an exposure-induced mitochondrial neurogastrointestinal encephalomyopathy.

Nonantibiotic Effects of Fluoroquinolones in Mammalian Cells

Fluoroquinolones (FQ) are powerful broad-spectrum antibiotics whose side effects include renal damage and, strangely, tendinopathies. The pathological mechanisms underlying these toxicities are poorly understood. Here, we show that the FQ drugs norfloxacin, ciprofloxacin, and enrofloxacin are powerful iron chelators comparable with deferoxamine, a clinically useful iron-chelating agent. We show that iron chelation by FQ leads to epigenetic effects through inhibition of α-ketoglutarate-dependent dioxygenases that require iron as a co-factor. Three dioxygenases were examined in HEK293 cells treated with FQ. At sub-millimolar concentrations, these antibiotics inhibited jumonji domain histone demethylases, TET DNA demethylases, and collagen prolyl 4-hydroxylases, leading to accumulation of methylated histones and DNA and inhibition of proline hydroxylation in collagen, respectively. These effects may explain FQ-induced nephrotoxicity and tendinopathy. By the same reasoning, dioxygenase inhibition by FQ was predicted to stabilize transcription factor HIF-1α by inhibition of the oxygen-dependent hypoxia-inducible transcription factor prolyl hydroxylation. In dramatic contrast to this prediction, HIF-1α protein was eliminated by FQ treatment. We explored possible mechanisms for this unexpected effect and show that FQ inhibit HIF-1α mRNA translation. Thus, FQ antibiotics induce global epigenetic changes, inhibit collagen maturation, and block HIF-1α accumulation. We suggest that these mechanisms explain the classic renal toxicities and peculiar tendinopathies associated with FQ antibiotics.

Fluoroquinolone-mediated Achilles rupture: a case report and review of the literature

Fluoroquinolone use for the treatment of bacterial infections is a common practice for foot and ankle surgeons because of its rather broad-spectrum coverage against common pathogens, good tissue penetration, and high bioavailability. An associated risk of tendinopathy has been reported in published studies, although tendon rupture has been much less frequent. In addition, tendinopathy has been more commonly reported with earlier generations of fluoroquinolones. We present a case of levofloxacin-mediated Achilles rupture that was complicated by the presence of an infected hematoma and abscess and subsequent long-term postoperative follow-up data, with a review of the literature.

Toxicological assessment of trace β-diketone antibiotic mixtures on zebrafish (Danio rerio) by proteomic analysis

β-Diketone antibiotics (DKAs) can produce chronic toxicity in aquatic ecosystems due to their pseudo-persistent in the environment. In this study, after long-term DKA exposure to zebrafish (Danio rerio), 47 protein spots had greater than 2-fold differential expression as compared to the control; there were 26 positive proteins with 14 up-regulated and 12 down-regulated. The main functions of the differentially expressed proteins were related to signal transduction mechanisms and the cytoskeleton. Of the 26 target genes, 11 genes were consistent between their transcriptional and translational levels. Low dose DKA exposure (4.69 and 9.38 mg/L) stimulated spontaneous movement in zebrafish. Changes in both creatine kinase activity and creatine concentration showed a similar trend to zebrafish activity. There was no obvious change in SV-BA after DKA exposure, while a reduction of heart rate was concomitant with increasing DKA concentrations. DKAs also induced severe histopathological changes in zebrafish heart tissue, such as dissolution of cristae and vacuolation of mitochondria. These results demonstrated that trace-level DKA exposure affects a variety of cellular and biological processes in zebrafish.

Antibiotic precautions in athletes

CONTEXT

Antibiotics are the mainstay of treatment for bacterial infections in patients of all ages. Athletes who maximally train are at risk for illness and various infections. Routinely used antibiotics have been linked to tendon injuries, cardiac arrhythmias, diarrhea, photosensitivity, cartilage issues, and decreased performance.

EVIDENCE ACQUISITION

Relevant articles published from 1989 to 2012 obtained through searching MEDLINE and OVID. Also, the Food and Drug Administration website was utilized.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 3.

RESULTS

The team physician should consider alternative medications in place of the "drug of choice" when adverse drug effects are a concern for an athlete's health or performance. If alternative medications cannot be selected, secondary preventative measures, including sunscreen or probiotics, may be needed.

CONCLUSION

Physicians choose medications based on a variety of factors to help ensure infection resolution while limiting potential side effects. Extra precautions are indicated when treating athletes with certain antibiotics.

Embryotoxic and teratogenic effects of norfloxacin in pregnant female albino rats

This study was designed to investigate the possible developmental teratogenicity of norfloxacin in rats. Forty pregnant female rats were divided into four equal groups. Group A received norfloxacin in a dose of 500 mg/kg·b·wt/day orally from 6th to 15th day of gestation. Groups B and C received 1000 and 2000 mg/kg·b·wt/day orally for the same period, respectively; Group D behaved as control and received 0.5 mL distilled water orally for the same period. The dams were killed on 20th day of gestation and their fetuses were subjected to morphological, visceral, and skeletal examinations. Norfloxacin significantly decreased the number of viable fetuses, increased the number of resorbed fetuses, and induced retardation in growth of viable fetuses; some visceral and skeletal defects in these fetuses were seen and these effects were dose dependant. Conclusively, norfloxacin caused some fetal defects and abnormalities, so it is advisable to avoid using this drug during pregnancy.

Oral fluoroquinolones and the incidence of rhegmatogenous retinal detachment and symptomatic retinal breaks: a population-based study

OBJECTIVE

To examine whether oral fluoroquinolone antibiotics are associated with an increase in subsequent rhegmatogenous retinal detachment and symptomatic retinal breaks in a large population-based cohort.

DESIGN

Population-based cohort study.

PARTICIPANTS AND CONTROLS

Adult residents of Olmsted County, Minnesota, who were prescribed oral fluoroquinolone medications from January 1, 2003, to June 30, 2011. Comparison cohorts consisted of patients prescribed oral macrolide and β-lactam antibiotics during the study period.

METHODS

Procedure codes were used to identify retinal detachment repair and prophylaxis procedures occurring within 1 year of prescription dates. Travel clinic, pro re nata, and self-treatment prescriptions were excluded. Patients with tractional retinal detachment, previous retinal detachment repair, endophthalmitis, and necrotizing retinitis were excluded, as were those with intraocular surgery or severe head/eye trauma ≤90 days before the procedure.

MAIN OUTCOME MEASURES

Rates of retinal detachment repair and prophylaxis procedures within 7, 30, 90, and 365 days of the first prescription were calculated and compared between antibiotic prescription cohorts using chi-square tests. Retinal detachment repair rates also were compared with the expected Olmsted County, Minnesota, rates using the one-sample log-rank test.

RESULTS

Oral fluoroquinolones were prescribed for 38,046 patients (macrolide n = 48,074, β-lactam n = 69,079) during the study period. Retinal detachment repair procedures were performed within 365 days of the first prescription in 0.03% (95% confidence interval [CI], 0.01-0.06) of the fluoroquinolone cohort, 0.02% (95% CI, 0.01-0.03) of the macrolide cohort, and 0.03% (95% CI, 0.02-0.05) of the β-lactam cohort (P > 0.05). Retinal detachment prophylaxis procedures for symptomatic retinal breaks were performed within 365 days of the first prescription in 0.01% (95% CI, 0.00-0.03) of the fluoroquinolone cohort, 0.02% (95% CI, 0.01-0.04) of the macrolide cohort, and 0.02% (95% CI, 0.01-0.04) of the β-lactam cohort (P > 0.05). Similar comparisons of treatment rates within 7, 30, and 90 days of the first prescription were all nonsignificant between cohorts. Post-fluoroquinolone retinal detachment repair rates were similar to expected rates (36.8 per 100,000/year vs. 28.8 per 100,000/year for age- and sex-matched historical rates, P = 0.35).

CONCLUSIONS

Oral fluoroquinolone use was not associated with an increased risk of rhegmatogenous retinal detachment or symptomatic retinal breaks in this population-based study.

Hinged circular fixator construct for correction of congenital metatarsal deformity in a foal

A five-week-old American Quarter Horse colt was presented for evaluation of a left hindlimb deformity and lameness. Radiographs of the left hindlimb revealed a varus deformity with recurvatum originating in the mid-diaphysis of the third metatarsal bone. Surgical correction was undertaken by performing an osteotomy through the centre of rotation of angulation located within the mid-diaphysis of the third metatarsal bone, and a four-ring hinged circular external fixator construct was applied. Distraction of the osteotomy site was performed over an 11 day period. Notable complications included failure of a fixation pin, infection of the surgical site, and temporary laxity of the supporting tendons and ligaments of the contralateral metatarsophalangeal joint. The fixator was maintained until there was sufficient bone formation to allow frame removal, 152 days after the initial surgery. Use of a hinged circular construct allowed for partial correction of the deformity with resultant lengthening and resolution of the lameness in this colt.

Healing of subcutaneous tendons: Influence of the mechanical environment at the suture line on the healing process

Tendon ruptures remain a significant musculoskeletal injury. Despite advances in surgical techniques and procedures, traditional repair techniques maintain a high incidence of rerupture or tendon elongation. Mechanical loading and biochemical signaling both control tissue healing. This has led some researchers to consider using a technique based on tension regulation at the suture line for obtaining good healing. However, it is unknown how they interact and to what extent mechanics control biochemistry. This review will open the way for understanding the interplay between mechanical loading and the process of tendon healing.

Severe shoulder tendinopathy associated with levofloxacin

Fluoroquinolone (FQ)-associated tendinopathy and myopathy are uncommon but well recognized complications of the use of this class of antibacterial agents. The case of a 63-year-old previously asymptomatic female patient who developed severe left shoulder tendinopathy after surreptitiously doubling the prescribed dose of levofloxacin for the treatment of community-acquired pneumonia is reported here. Surgical stabilization with suture anchors and subacromial decompression were needed.

Fluoroquinolone toxicity symptoms in a patient presenting with low back pain

Fluoroquinolone medications have been shown to contribute to tendinopathies, cardiotoxicity, and neurotoxicity. Low back pain is a common musculoskeletal condition for which chiropractic treatment is most often sought. This case report details a patient presenting with low back pain and a history of fluoroquinolone toxicity. The patient was initially treated with chiropractic manipulation, which increased her symptoms. She was then referred to an osteopathic physician who treated the patient with intravenous antioxidants and amino acids, an elimination diet, and probiotic supplementation. Within 4 months of therapy, the patient reported a decrease in pain, a resolution of her dizziness, shortness of breath, panic attacks, tachycardia, and blurred vision. After an additional 8 weeks of antioxidant therapy, she reported further reductions in pain and improved disability. People susceptible to fluoroquinolone toxicity may present with common musculoskeletal symptoms. A past medical history and medication history may help to identify this population of patients. People presenting with fluoroquinolone toxicity may have unidentified contributing factors that predispose them to this anomaly. This patient reported improvements in pain and disability following antioxidant amino acid therapy for a total of 6 months. The natural history of fluoroquinolone toxicity is unknown and may account for the observed improvements.

Minimally invasive monitoring of skeletal muscle hypermetabolism induced by the phosphodiesterase-III-inhibitor milrinone and sodium fluoride

OBJECTIVES

We hypothesized that the phosphodiesterase-III-inhibitor milrinone and the non-specific G-protein activator sodium fluoride increase the skeletal muscular lactate levels as a sign of a hypermetabolic response.

METHODS

With approval of the local animal care committee Sprague-Dawley rats were killed and artificially perfused either with Ringer's solution or sodium fluoride 110 mM, while milrinone 1.32 mM or Ringer's solution at 1 μl/min was applied via microdialysis probes in both hind limbs. Lactate was measured spectrophotometrically in the dialysate.

KEY FINDINGS

Baseline lactate levels before drug application did not differ between hind limbs. Local infusion of milrinone via microdialysis did not significantly increase intramuscular lactate concentrations compared with the Ringer control group. Muscular perfusion with sodium fluoride resulted in a significant increase of lactate and was potentiated by combination with local milrinone.

CONCLUSIONS

Phosphodiesterase-III-inhibition alone does not significantly influence the lactate levels in skeletal muscle of sacrificed rats. Sodium fluoride infusion leads to an intramuscular lactate increase, which was further potentiated by local inhibition of phosphodiesterase-III. The fluoride-mediated hypermetabolic response following sodium fluoride could be a possible explanation for the observed myotoxic adverse effects in individuals treated by fluoride-containing agents.

Methicillin-resistant Staphylococcus aureus: an overview for manual therapists()

OBJECTIVE

Methicillin-resistant Staphylococcus aureus (MRSA) is associated with difficult-to-treat infections and high levels of morbidity. Manual practitioners work in environments where MRSA is a common acquired infection. The purpose of this review is to provide a practical overview of MRSA as it applies to the manual therapy professions (eg, physical and occupational therapy, athletic training, chiropractic, osteopathy, massage, sports medicine) and to discuss how to identify and prevent MRSA infections in manual therapy work environments.

METHODS

PubMed and CINAHL were searched from the beginning of their respective indexing years through June 2011 using the search terms MRSA, methicillin-resistant Staphylococcus aureus, and Staphylococcus aureus. Texts and authoritative Web sites were also reviewed. Pertinent articles from the authors' libraries were included if they were not already identified in the literature search. Articles were included if they were applicable to ambulatory health care environments in which manual therapists work or if the content of the article related to the clinical management of MRSA.

RESULTS

Following information extraction, 95 citations were included in this review, to include 76 peer-reviewed journal articles, 16 government Web sites, and 3 textbooks. Information was organized into 10 clinically relevant categories for presentation. Information was organized into the following clinically relevant categories: microbiology, development of MRSA, risk factors for infection, clinical presentation, diagnostic tests, screening tests, reporting, treatment, prevention for patients and athletes, and prevention for health care workers.

CONCLUSION

Methicillin-resistant S aureus is a health risk in the community and to patients and athletes treated by manual therapists. Manual practitioners can play an essential role in recognizing MRSA infections and helping to control its transmission in the health care environment and the community. Essential methods for protecting patients and health care workers include being aware of presenting signs, patient education, and using appropriate hand and clinic hygiene.