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Medicina do trabalho- laboral

#¿Cuánto dura una #prótesis de cadera o de #rodilla?

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Una investigación que recopila datos de miles de pacientes de seis países concluye que ocho de cada diez prótesis de rodilla y seis de cada diez de cadera se mantienen a los 25 años.

Prótesis de cadera y de rodilla.
Universidad de Bristol

Un metanálisis sobre miles de pacientes, cuyos datos se remontan a 25 años en seis países concluye que las prótesis de rodilla y cadera tienen unas elevadas tasas de éxito. En concreto, ocho de cada diez reemplazos de rodilla y seis de cada diez de cadera siguen funcionando al cabo de los 25 años.

La investigación se publica en The Lancet, financiada por el Registro Nacional de Articulaciones británico. Los autores principales son de la Unidad de Investigación Musculoesquelética, en la Universidad de Bristol.

En Reino Unido, se han efectuado más de dos millones de reemplazos de cadera y de rodilla desde 2003, según datos aportados en el estudio. “A menudo los pacientes nos preguntan cuánto durará su prótesis, pero hasta ahora no teníamos una respuesta generalizable”, dice el autor principal, Jonathan Evans, de la Universidad de Bristol. “Los estudios anteriores se han basado en muestras mucho más pequeñas. En el mejor de los casos, el Servicio Nacional de Salud [el británico NHS] solo podía informar sobre el tiempo de duración para el que están diseñadas las prótesis, en lugar de recurrir a la evidencia basada en la experiencia de múltiples pacientes. Teniendo en cuenta la mejora en tecnología y en las técnicas de los últimos 25 años, esperamos que los reemplazos colocados hoy puedan durar aún más”.

Los investigadores revisaron 150 series de casos relacionados con reemplazos de cadera y 33 con los de rodilla, así como seis registros nacionales de Australia, Dinamarca, Finlandia, Nueva Zelanda, Noruega y Suecia. En total, se analizaron informes de 215.676 personas cuyos casos fueron seguidos durante 15 años después de someterse a reemplazos totales de cadera; 74.052, seguidos durante 20 años, y 51.359, durante 25 años.

El 89% de las prótesis de cadera duraron 15 años, el 70%, 20 años y el 58% llegaron hasta los 25 años. Con los reemplazos totales de rodilla, los resultados variaron según la prótesis fuera total o parcial: el 93% de los reemplazos totales y el 77% de los parciales duraron 15 años. El 90% de los totales y el 72% de los parciales se prolongaron durante 20 años. El 82% de los totales y el 70% de los parciales cumplieron los 25 años.

#Tensão arterial alta antes dos 40 anos pode aumentar risco cardiovascular

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Fonte de imagem: myDr

As pessoas com menos de 40 anos que apresentam tensão arterial elevada correm um maior risco de insuficiência cardíaca, acidente vascular cerebral (AVC) e obstruções nas artérias mais tarde, anunciou um estudo.

O estudo que foi conduzido por investigadores da Faculdade de Medicina da Universidade Duke, EUA, analisou dados de mais de 4.800 participantes de outro estudo norte-americano, conhecido como CARDIA, que avaliava o risco de doença coronária em adultos mais jovens.

Os participantes tinham tido a tensão arterial medida antes dos 40 anos de idade. Os investigadores usaram as novas diretrizes para a tensão arterial, adotadas nos EUA em 2017, que decrescem os valores da definição clínica de tensão arterial elevada.

Assim, os participantes no estudo foram divididos em quatro grupos, de acordo com os seguintes níveis de tensão arterial estabelecidos em 2017: normal (120 ou inferior sistólica e 80 ou menos diastólica), elevada (120-129 e menos de 80), hipertensão de nível 1 (130-139 e 80-89) e hipertensão de nível 2 (140 ou mais e 90 ou mais).

Os investigadores seguiram os participantes para identificar eventuais eventos cardiovasculares graves, durante uma média de cerca de 19 anos. Durante o período de monitorização ocorreram 228 episódios. A equipa observou, sucessivamente, maiores índices de eventos que coincidiram com valores mais elevados de tensão arterial.

“Nos jovens adultos, os que tinham tensão arterial elevada, hipertensão de nível 1 e hipertensão de nível 2 antes dos 40 anos de idade, tal como definido nas diretrizes de 2017, apresentavam um risco significativamente superior de eventos subsequentes de doenças cardiovasculares, em comparação com os que tinham tensão arterial normal antes dos 40 anos de idade”, concluiu Yuichiro Yano, investigador que liderou o estudo.

Os autores consideram que identificar e tratar problemas de tensão arterial atempadamente em jovens adultos, segundo as novas diretrizes norte-americanas, poderá ser benéfico para aquela população.

 

Banco da Saúde

#Vertigo (Symptoms, Causes, Treatments, and Home Remedies)

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A view from the top of an escaltor warps, giving a feeling of vertigo.

Source: Getty Images

What is vertigo?

Vertigo is a sense of rotation, rocking, or the world spinning, experienced even when someone is perfectly still.

Many children attempt to create a sense of vertigoby spinning around for a time; this type of induced vertigo lasts for a few moments and then disappears. In comparison, when vertigo occurs spontaneously or as a result of an injury it tends to last for many hours or even days before resolving.

Sound waves travel through the outer ear canal until they reach the ear drum. From there, sound is turned into vibrations, which are transmitted through the inner ear via three small bones — the incus, the malleus, and the stapes — to the cochlea and finally to the vestibular nerve, which carries the signal to our brain. Another important part of the inner ear is the collection of semicircular canals. These are positioned at right angles to each other, and are lined with sensitive cells to act like a gyroscope for the body. This distinctive arrangement, in combination with the sensitivity of the hair cells within the canals, provides instantaneous feedback regarding our position in space.

Picture of the outer and inner structures of the ear.

Picture of the outer and inner structures of the ear.

women with dizziness

Vertigo and Dizziness

Vertigo is a feeling that you are dizzily turning around or that your surroundings are dizzily turning about you. Vertigo is medically distinct from dizziness, lightheadedness, and unsteadiness in that vertigo involves the sensation of movement.

A woman holds her head, dizzy with vertigo.

Source: iStock

What are the signs and symptoms of vertigo?

The symptoms of vertigo include a sense of spinning or moving. These symptoms can be present even when someone is perfectly still. Movement of the head or body, like rolling over in bed, can escalate or worsen the symptoms. The symptoms are different from lightheadedness or a sense of fainting. Many people experience associated nausea or vomiting.

Physical examination often shows signs of abnormal eye movements, called nystagmus. Some patients experience imbalance in association with the vertigo. If imbalance lasts for more than a few days, or if the vertigo is accompanied by weakness or incoordination of one side of the body, the suspicion of stroke or other problem of the brain is much higher. In those cases, prompt evaluation is recommended.

A MRI of the brain and spinal cord.

Source: Getty Images

What causes vertigo?

There are a number of different causes of vertigo. Vertigo can be defined based upon whether the cause is peripheral or central. Central causes of vertigo arise in the brain or spinal cord while peripheral vertigo is due to a problem within the inner ear. The inner ear can become inflamed because of illness, or small crystals or stones found normally within the inner ear can become displaced and cause irritation to the small hair cells within the semicircular canals, leading to vertigo. This is known as benign paroxysmal positional vertigo (BPPV).

Meniere’s disease, vertigo associated with hearing loss and tinnitus (ringing in the ear), is caused by fluid buildup within the inner ear; the cause of this fluid accumulation is unknown. Head injuries may lead to damage to the inner ear and be a cause of vertigo. Infrequently, strokes affecting certain areas of the brain, multiple sclerosis, or tumors may lead to an onset of vertigo. Some patients with a type of migraine headache called basilar artery migraine may develop vertigo as a symptom.

Balance Disorders: Vertigo, Migraines, Motion Sickness and MoreBalance Disorders Slideshow

Take the Vertigo Quiz

Tinnitus: Why Are My Ears Ringing?Tinnitus Slideshow: Why Are My Ears Ringing?

A collage shows possibles causes of dizziness such as head injuries, medications and alcohol.

Source: Getty Images

What are the risk factors for vertigo?

Head injuries may increase the risk of developing vertigo, as can different medications, including some antiseizure medications, blood pressure medications, antidepressants, and even aspirin. Anything that may increase your risk of stroke(high blood pressureheart diseasediabetes, and smoking) may also increase your risk of developing vertigo. For some people, drinking alcohol can cause vertigo.

Studies of the incidence of vertigo find that between 2% to 3% of a population is at risk of developing BPPV; older women seem to have a slightly higher risk of developing this condition.

A doctor conducts a visual coordination exam on a young woman.

Source: iStock

How is vertigo diagnosed?

During an evaluation for vertigo, the health care professional may obtain a full history of the events and symptoms. This includes medications that have been taken (even over-the-counter medications), recent illnesses, and prior medical problems (if any). Even seemingly unrelated problems may provide a clue as to the underlying cause of the vertigo.

After the history is obtained, a physical examination is performed. This often involves a full neurologic exam to evaluate brain function and determine whether the vertigo is due to a central or peripheral cause. New symptoms of vertigo should be worked up to rule out stroke as the primary cause. History, physical exam, and imaging as needed are critical to insure any life-threatening conditions are ruled out. Signs of nystagmus (abnormal eye movements) or incoordination can help pinpoint the underlying problem. The Dix-Hallpike test is done to try to recreate symptoms of vertigo; this test involves abruptly repositioning the patient’s head and monitoring the symptoms which might then occur. However, not every patient is a good candidate for this type of assessment, and a physician might instead perform a “roll test,” during which a patient lies flat and the head is rapidly moved from side to side. Like the Dix-Hallpike test, this may recreate vertigo symptoms and may be quite helpful in determining the underlying cause of the vertigo.

If indicated, some cases of vertigo may require an MRI or CT scan of the brain or inner ears to exclude a structural problem like stroke. If hearing loss is suspected, audiometry may be ordered. Hearing loss is not seen with BPPV or other common causes of vertigo. Electronystagmography, or electrical evaluation of vertigo, can help distinguish between peripheral and central vertigo, but is not routinely performed.

A physical therapist helps a patient with head exercises to treat vertigo.

Source: iStock

What is the treatment for vertigo?

Some of the most effective treatments for peripheral vertigo include particle repositioning movements. The most well-known of these treatments is the Epley maneuver or canalith repositioning procedure. During this treatment, specific head movements lead to movement of the loose crystals (canaliths) within the inner ear. By repositioning these crystals, they cause less irritation to the inner ear and symptoms can resolve. Because these movements can initially lead to worsening of the vertigo, they should be done by an experienced health care professional or physical therapist.

Cawthorne head exercises, or vestibular rehabilitation habituation exercises, are a series of eye and head movements which lead to decreased sensitivity of the nerves within the inner ear and subsequent improvement of vertigo. These simple movements need to be practiced by the patient on a regular basis for best results.

Medications may provide some relief, but are not recommended for long-term use. Meclizine is often prescribed for persistent vertigo symptoms, and may be effective. Benzodiazepine medications like diazepam (Valium) are also effective but may cause significant drowsiness as a side effect. Other medications may be used to decrease nausea or vomiting. It is should be recognized that medications can provide symptomatic relief, but are not considered “cures” for vertigo.

A woman lays on the floor at home performing head exercises for vertigo treatment.

Source: Getty Images

Are home remedies effective for treating vertigo?

 

While several suggestions for treatment of vertigo can be found, most of these are ineffective. Many cases of vertigo resolve spontaneously within a few days, which may promote the belief that a certain home remedy has been beneficial in resolving the symptoms.

The vestibular rehabilitation exercises (Cawthorne head exercises) or modified Epley maneuvers are meant to be done on a regular basis by patients, and may lead to marked improvements in vertigo.

A woman pours salt out of a salt shaker.

Source: Getty Images

Can vertigo be prevented?

Controlling risk factors for stroke may decrease the risk of developing central vertigo. This includes making sure that blood pressure, cholesterol, weight, and blood glucose levels are in optimal ranges. To decrease symptoms of vertigo in cases of Meniere’s disease, controlling salt intake may be helpful. If peripheral vertigo has been diagnosed, then performing vestibular rehabilitation exercises routinely may help prevent recurrent episodes.

As most cases of vertigo occur spontaneously, it is difficult to predict who is at risk; as such, complete avoidance or prevention may not be possible. However, maintaining a healthy lifestyle will decrease the risks of experiencing this condition.

From WebMD Logo

#Foot and Ankle #Osteoarthritis

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As you age, your chance of developing osteoarthritis, which is caused by wear and tear, increases. The joint damage associated with osteoarthritis causes swelling, pain, and deformity. Here is information about how osteoarthritis affects the foot and ankle and information you can use to help you manage this debilitating condition.

What Is Arthritis?

Arthritis is a general term for a group of more than 100 diseases. The word “arthritis” means “joint inflammation.” Arthritis involves inflammation and swelling in and around the body’s joints and surrounding soft tissue. The inflammation can cause pain and stiffness.

In many kinds of arthritis, progressive joint deterioration occurs and the smooth “cushioning” cartilage in joints is gradually lost. As a result, the bones rub and wear against each other. Soft tissues in the joints also may begin to wear down. Arthritis can be painful and eventually result in limited motion, loss of joint function, and deformities in the joints affected.

What Is Osteoarthritis?

Osteoarthritis, or “wear-and-tear” arthritis, is the most common type of arthritis. Also known as degenerative joint disease or age-related arthritis, osteoarthritis is more likely to develop as people age. Inflammation and injury to the joint cause a breaking down of cartilage tissues, resulting in pain, swelling, and deformity. The changes in osteoarthritis usually occur slowly over many years, though there are occasional exceptions.

How Does Osteoarthritis Affect the Foot and Ankle?

Each foot has 28 bones and more than 30 joints. The following are the most common foot joints affected by osteoarthritis:

  • The three joints of the foot that involve the heel bone, the inner mid-foot bone, and the outer mid-foot bone
  • The joint of the big toe and foot bone
  • The joint where the ankle and shinbone meet

What Are the Symptoms of Foot and Ankle Osteoarthritis?

Symptoms of foot and ankle osteoarthritis often include:

  • Tenderness or pain
  • Reduced ability to move, walk, or bear weight
  • Stiffness in the joint
  • Swelling in the joint

How Is Foot and Ankle Osteoarthritis Diagnosed?

The diagnosis of foot and ankle osteoarthritis most likely will involve:

How Is Foot and Ankle Osteoarthritis Treated?

Foot and ankle osteoarthritis can be treated in many ways. Nonsurgical methods to treat foot and ankle arthritis include:

  • Steroid medicationsinjected into the joints
  • Anti-inflammatory drugs to reduce swelling in the joints
  • Pain relievers
  • Pads or arch supports
  • Canes or braces to support the joints
  • Inserts that support the ankle and foot (orthotics)
  • Physical therapy
  • Custom shoes
  • Weight control

Tips on Foot Care With Osteoarthritis

The most essential element of foot care for people with foot and ankle osteoarthritis is to wear shoes that fit properly and feel comfortable. The following are things to look for in finding a comfortable shoe:

  • Shoes shaped like your foot
  • Shoes that have support — for example, no slip-on shoes
  • Rubber soles to provide more cushioning
  • Flexibility
  • Proper fit — ask the salesperson to help you with this

Exercise can help keep your feet pain-free, strong, and flexible. Exercises that can be good for your feet include:

  • Achilles stretch. With your palms flat on a wall, lean against the wall and place one foot forward and one foot back. Lean forward, leaving your heels on the floor. You can feel the pull in your Achilles tendon and your calf. Repeat this exercise three times, holding for 10 seconds on each repeat.
  • Big-toe stretch. Place a thick rubber band around your big toes. Pull the big toes away from each other and toward the other toes. Hold this position for five seconds and repeat the exercise 10 times.
  • Toe pull. Place a rubber band around the toes of each foot, and then spread your toes. Hold this position for five seconds and repeat the exercise 10 times.
  • Toe curl. Pick up marbles with your toes.

Is Surgery an Option for Foot and Ankle Osteoarthritis?

More than one kind of surgery may be required to treat foot and ankle osteoarthritis. Your doctor can select the kind of surgery that is best for you, depending on the extent of your arthritis. The following are some of the surgical options for foot and ankle osteoarthritis:

  • Fusion surgery. This kind of surgery, also called arthrodesis, involves fusing bones together with the use of rods, pins, screws, or plates. After healing, the bones remain fused together.
  • Joint replacement surgery. This kind of surgery involves replacing the ankle joint with artificial implants and is used only in rare cases.

#TERAPIA DE CANCRO DESCOBERTA EM COIMBRA ESTÁ A REVELAR-SE EFICAZ

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TERAPIA DE CANCRO DESCOBERTA EM COIMBRA ESTÁ A REVELAR-SE EFICAZ

“Vários estudos e experiências provaram a eficácia da molécula Redaporfin” no tratamento de diversos tipos de cancro. Primeiro fármaco português para tratamentos oncológicos poderá estar no mercado “dentro de três a quatro anos”.
Foto: Noticias.uc.pt
Uma molécula para terapia inovadora no tratamento de vários tipos de cancro, patenteada pela Universidade de Coimbra (UC), está a revelar, de acordo com os estudos efetuados, a “eficácia desejada”, anunciou hoje esta instituição.
“Vários estudos e experiências realizadas em ratinhos, entre 2011 e 2014, provaram a eficácia da molécula Redaporfin”, descoberta na UC, para o tratamento de diversos tipos de cancro, “através de terapia fotodinâmica” (tratamento inovador que “permite eliminar células cancerígenas de forma precisa”), afirma a UC numa nota hoje divulgada.
De acordo com os ensaios realizados, “86% dos ratinhos com tumores diversos que foram tratados com esta tecnologia, seguindo exigentes protocolos de segurança, ficaram curados”, salienta a mesma nota, adiantando que “não se observaram efeitos secundários, como acontece com os tratamentos convencionais”, como a quimioterapia.
O estudo, que acaba de ser publicado no European Journal of Cancer, demonstrou igualmente uma “taxa de reincidência da doença muitíssimo baixa”, revelando a eficácia do fármaco.
Os testes efetuados “previram com rigor quando é que a resposta ao tratamento iria surgir, com que doses e em que circunstâncias seriam obtidos os efeitos terapêuticos no doente”, salienta o diretor da química medicinal deste projeto, Luís Arnaut.
As previsões estão a ser “confirmadas nos ensaios clínicos em curso”, acrescenta o investigador da UC.
Esta confirmação é “excecional” porque, “na grande maioria dos estudos, muito do conhecimento adquirido nos testes em animais não é confirmado nos humanos”, mas “neste caso foi possível chegar à dose adequada para obter resultado terapêutico nos doentes sem efeitos adversos, como previsto”, explica Luís Arnaut.

Estão a decorrer ensaios com doentes oncológicos em hospitais portugueses até ao final deste ano e os resultados já conhecidos e validados cientificamente “fundamentam a expectativa” de que a terapia fotodinâmica com a molécula Redaporfin se revele “mais eficaz que as terapêuticas convencionais”, admite Luís Arnaut.
Grande parte do percurso está feita e o primeiro fármaco português para tratamentos oncológicos poderá estar no mercado “dentro de três a quatro anos”, acredita o investigador e catedrático do Departamento de Química da UC.
Iniciada há mais de uma década, a investigação envolve perto de quatro dezenas de investigadores dos grupos de Luís Arnaut e de Mariette Pereira, da UC, da empresa Luzitin SA (criada para desenvolver este projeto), e de uma equipa de médicos do Instituto Português de Oncologia do Porto.

O aspeto mais inovador do tratamento fotodinâmico com Redaporfin reside no facto de “estimular o sistema imunitário do paciente, ou seja, a terapia limita o processo de metastização do tumor”, isto é, “o sistema imunitário fica alerta e ativa a proteção antitumoral contra o mesmo tipo de células cancerígenas noutras partes do organismo”, conclui Luís Arnaut.
Fundada, em 2010, pela Bluepharma e inventores da Redaporfin, a Luzitin — que realizou os estudos de pré-clínicos para obter autorização para a realização de ensaios clínicos com a Redaporfin – está, desde 2014, a realizar em Portugal um ensaio clínico de fase I/II com doentes de cancro avançado da cabeça e pescoço.
A Luzitin SA é financiada pela farmacêutica de Coimbra Bluepharma e pela sociedade de capital de risco Portugal Ventures.
Fonte: DN

#Fixed Low-Dose Triple Combination Antihypertensive Medication vs Usual Care for Blood Pressure Control

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Fixed Low-Dose Triple Combination Antihypertensive Medication vs Usual Care for Blood Pressure Control in Patients With Mild to Moderate Hypertension in Sri Lanka: A Randomized Clinical Trial.

Resultado de imagem para Mild-to-moderate hypertension: does low-dose triple antihypertensive drug combination improve BP control vs usual care?

Abstract

IMPORTANCE:

Poorly controlled hypertension is a leading global public health problem requiring new treatment strategies.

OBJECTIVE:

To assess whether a low-dose triple combination antihypertensive medication would achieve better blood pressure (BP) control vs usual care.

DESIGN, SETTING, AND PARTICIPANTS:

Randomized, open-label trial of a low-dose triple BP therapy vs usual care for adults with hypertension (systolic BP >140 mm Hg and/or diastolic BP >90 mm Hg; or in patients with diabetes or chronic kidney disease: >130 mm Hg and/or >80 mm Hg) requiring initiation (untreated patients) or escalation (patients receiving monotherapy) of antihypertensive therapy. Patients were enrolled from 11 urban hospital clinics in Sri Lanka from February 2016 to May 2017; follow-up ended in October 2017.

INTERVENTIONS:

A once-daily fixed-dose triple combination pill (20 mg of telmisartan, 2.5 mg of amlodipine, and 12.5 mg of chlorthalidone) therapy (n = 349) or usual care (n = 351).

MAIN OUTCOMES AND MEASURES:

The primary outcome was the proportion achieving target systolic/diastolic BP (<140/90 mm Hg or <130/80 mm Hg in patients with diabetes or chronic kidney disease) at 6 months. Secondary outcomes included mean systolic/diastolic BP difference during follow-up and withdrawal of BP medications due to an adverse event.

RESULTS:

Among 700 randomized patients (mean age, 56 years; 58% women; 29% had diabetes; mean baseline systolic/diastolic BP, 154/90 mm Hg), 675 (96%) completed the trial. The triple combination pill increased the proportion achieving target BP vs usual care at 6 months (70% vs 55%, respectively; risk difference, 12.7% [95% CI, 3.2% to 22.0%]; P < .001). Mean systolic/diastolic BP at 6 months was 125/76 mm Hg for the triple combination pill vs 134/81 mm Hg for usual care (adjusted difference in postrandomization BP over the entire follow-up: systolic BP, -9.8 [95% CI, -7.9 to -11.6] mm Hg; diastolic BP, -5.0 [95% CI, -3.9 to -6.1] mm Hg; P < .001 for both comparisons). Overall, 419 adverse events were reported in 255 patients (38.1% for triple combination pill vs 34.8% for usual care) with the most common being musculoskeletal pain (6.0% and 8.0%, respectively) and dizziness, presyncope, or syncope (5.2% and 2.8%). There were no significant between-group differences in the proportion of patient withdrawal from BP-lowering therapy due to adverse events (6.6% for triple combination pill vs 6.8% for usual care).

CONCLUSIONS AND RELEVANCE:

Among patients with mild to moderate hypertension, treatment with a pill containing low doses of 3 antihypertensive drugs led to an increased proportion of patients achieving their target BP goal vs usual care. Use of such medication as initial therapy or to replace monotherapy may be an effective way to improve BP control.

Author information

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#DIFERENT CLASSES OF ANTIBIOTICS

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Resultado de imagem para antibiotics

 

Bacteria themselves can be divided into two broad classes – Gram-positive and Gram-negative. The classes derive these names from the Gram test, which involves the addition of a violet dye to the bacteria. Gram-positive bacteria retain the colour of the dye, whilst Gram-negative bacteria do not, and are instead coloured red or pink. Gram-negative bacteria are more resistant to antibodies and antibiotics than Gram-positive bacteria, because they have a largely impermeable cell wall. The bacteria responsible for MRSA and acne are examples of Gram-positive bacteria, whilst those responsible for Lyme disease and pneumonia are examples of Gram-negative bacteria. Beta-Lactams Beta-lactams are a wide range of antibiotics, the first of which to be discovered was penicillin, which Alexander Fleming identified in 1928. All beta-lactam antibiotics contain a beta-lactam ring; they include penicillins, such as amoxicillin, and cephalosporins. Bacteria can develop resistance to beta-lactams via several routes, including the production of enzymes that break down the beta-lactam ring. In the NHS, penicillins are the most commonly prescribed antibiotics, with amoxicillin being the most common in the class. Sulfonamides Prontosil, a sulfonamide, was the first commercially available antibiotic, developed in 1932. In the present day, sulfonamides are rarely used, partially due to the development of bacterial resistance, but also due to concern about unwanted effects such as damage to the liver of patients. Aminoglycosides Aminoglycosides inhibit the synthesis of proteins in bacteria, eventually leading to cell death. In the treatment of tuberculosis, streptomycin was the first drug found to be effective; however, due to issues with toxicity of aminoglycosides, their present day use is limited. Tetracyclines Tetracyclines are broad-spectrum antibiotics, active against both Gram-positive and Gram-negative bacteria. Their use is decreasing to increasing instances of bacterial resistance; however, they still find use in treatment of acne, urinary tract, and respiratory tract infections, as well as chlamydia infections. Chloramphenicol Another broad-spectrum antibiotic, chloramphenicol also acts by inhibiting protein synthesis, and thus growth and reproduction of bacteria. Due to the possibility of serious toxic effects, in developed countries it is generally only used in cases where infections are deemed to be life-threatening, although it is a much more common antibiotic in developing countries due to its low cost and availability. Macrolides Macrolides’ effectiveness is marginally broader than that of penicillins, and they have been shown to be effective against several species of bacteria that penicillins are not. Whilst some bacterial species have developed resistance to macrolides, they are still the second most commonly prescribed antibiotics in the NHS, with erythromycin being the most commonly prescribed in the class. Glycopeptides Glycopeptides include the drug vancomycin – commonly used as a ‘drug of last resort’, when other antibiotics have failed. There are strict guidelines on the circumstances in which vancomycin can be used to treat infections, in order to delay the development of resistance. The bacteria against which glycopeptides are active are otherwise somewhat limited, and in most they inhibit growth and reproduction rather than killing bacteria directly. Oxazolidinones Oxazolidinones are active against Gram-positive bacteria, and act by inhibiting protein synthesis, and hence growth and reproduction. Linezolid, approved for use in 2000, was the first marketed antibiotic in the class, and resistance seems to be developing relatively slowly since its introduction. Ansamycins This class of antibiotics are effective against Gram-positive bacteria, as well as some Gram-negative bacteria. A subclass of antibiotics, rifamycins, are used to treat tuberculosis and leprosy. Uncommonly, ansamycins can also demonstrate anti-viral activity. Quinolones Quinolones are widely used for urinary tract infections, as well as other hospital-acquired infections where resistance to older classes of antibiotics is suspected. Resistance to quinolones can be particularly rapid in its development; in the US, they were the most commonly prescribed antibiotics in 2002, and their prescription for unrecommended conditions or viral infections is also thought to be a significant contributor to the development of resistance. Streptogramins Streptogramins are unusual in that they are usually administered as a combination of two antibiotic drugs from the different groups within the class; combined they have a synergistic effect and are capable of directly killing bacteria cells. They are often used to treat resistant infections, although resistance to the streptogramins themselves has also developed. Lipopeptides Discovered in 1987, lipopeptides are the most recent class of antibiotics. Daptomycin is the most commonly used member of the class; it has a unique mechanism of action, disrupting several aspects of cell membrane function in bacteria. This unique mechanism of action also seems to be advantageous in that, currently, incidences of resistance to the drug seem to be rare – though they have been reported. Below are some summaries and mind maps that will make learning antibiotics and their uses easier.

Read more at: https://forum.facmedicine.com/threads/antibiotics-types-and-mechanism-of-action.35444/

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