Chemotherapy regimens

ANTIMICROBIAL CHEMOTHERAPY REGIMENS

DOSE AND DURATION OF THERAPY

This varies depending on the nature, severity, and response to therapy. The long-term treatment (up to 6 weeks) is required for some varieties of infective endocarditis when pulmnary tuberculosis were treated for at least 6 months. Treat many common infections, improvement occurs within 2-3 days, when the patient is afebrile or leukocytosis have been resolved, the mouth should be considered in these parenteral therapy.Five started seven days of therapy is sufficient for most infections. A short course of therapy (3 days or less) should these symptoms of uncomplicated bacteria (cystitis), minimizing the duration of treatment reduces the risk of side effects and super-infection of Candida spp or Clostridium difficile, as well as the cost of care. Breasts that concentrates in the cell, such as erythromycin, quinolones and tetracyclines are used in the treatment of mycoplasma, brucellosis, and Legionella infections.

RENAL AND HEPATIC INSUFFICIENCY

Many drugs require dose reduction of renal failure to prevent toxic buildup. This is particularly true beta lactums and aminoglycosides. Nalidixic acid and tetracycline, other doxycyclines, should be avoided. This hepatic impairment, caution and the dose should be reduced by agents such as isoniazid, ketoconazole, rifampin, and interferon.

THERAPEUTIC DRUG MONITORING

In order to ensure more non-toxic concentrations of therapeutic drugs, drugs such as aminoglycosides and vancomycin serum monitored, especially those with impared renal or change function.Peak (after 1 hour - the dose) and through the (pre-dose) on serum samples be tested. However, the increasing use of once daily doses of aminoglycosides, but the time randm serum analysis are being adopted.

MECHANISMS OF ACTION AND RESISTANCE TO ANTIMICROBIAL AGENTS 

Antibiotic works in different places for bacteria. Penecillin, cephalosporins and vancomycin, erythromycin cell wall and protein synthesis aminoglycosides, rifampicin effect on RNA synthesis and effect of metronidazole, quinolones and DNA synthesis. Sulfonamides and trimethoprim are folic acid antagonists and amphotericin B to prevent the synthesis of fungal sterols. Antibiotic resistance may be due to:

•  Failure to reach the target site, for example, because the causes of deterioration of permeability does not reach the outer membrane of    bacteria (eg, penicillin and Gram-negative).
•  Enzyme inactivation (eg, enzymes beta-lactamase).
•  Change the target site (eg, a point mutation in E. coli penicillin binding protien Strep.pneumoniae lead to resistance.

The development or acquisition of resistance to an antibiotic that the bacteria always involves either a mutation in a single point in a gene or transfer of genetic material from another organism. large fragments of DNA can be introduced into bacteria either by transfer of " naked " DNA or by a bacteriophage (a virus) DNA vector.Both the past (processing), and one (transduction) depend integration of new DNA into the chromosomal DNA recipient. This requires a high degree of homology between donor and recipient of the chromosomal DNA. Finally, resistance to antibiotics can be transferred from one bacterium to another by conjugation, where DNA extrachromosomal (plasmid) that contains resistance factor (R factor) is transferred from one cell to another by contact Direct. Transfer of these plasmids R factors can occur between unrelated bacterial strains and involve large amounts of DNA and often code for multiple resistance antbiotic.

The transformation is probably the least clinically relevant mechanism, while the transduction and transfer of R factors are generally responsible for the immediate emergence of antibiotic resistance in bacteria, increasing resistance to many antibiotics has developed...... read more 

Bacterial infection of the central nervous system can cause abscesses

INFECTIONS OF THE NERVOUS SYSTEM 

 

The central nervous system or central nervous system includes the brain, spinal cord and membranes. In certain circumstances, bacteria can penetrate the central nervous system areas. If this occurs, abscesses or empyemas may be established. In general, the CNS is well defended against infection. The spine and brain are sheathed in hard, protective membrane. The outer membrane, the dura, and the next layer, the arachnoid, totally covering the brain and spinal cord. However, these defenses are not absolute. In rare cases, bacteria have access to areas of central nervous system.

 

There are four main causes of infections of the central nervous system (CNS): bacteria, viruses, fungi and protozoa.

 

Bacterial infection of the central nervous system can cause abscesses and empyema (accumulation of pus). Abscesses have fixed boundaries, but no definable shape and size empyema. CNS infections are classified according to where they occur. For example, a spinal epidural abscess is located above the dura mater, and subdural empyema occurs between the dura and arachnoid injury. As the pus and other material of an infection accumulate, pressure is exerted on the brain or spinal cord. This pressure can damage the nervous system tissue, perhaps permanently. Without treatment, CNS infection is fatal.

The brain is highly protected, and is essential for the maintenance of life. Yet the central nervous system infections are occurring. They range from a latent is rapidly fatal. This guide describes some of the features of CNS infection and laboratory diagnosis. The membranes surrounding the brain infections called meningitis. When the content of the brain that is infected with meningitis. brain abscesses are defined, localized lesions within the brain. "Slow" brain infections also occur, and these are usually fatal. Rapid diagnosis of CNS infections is important because many of the central nervous system infections are life threatening.

 

Viruses that infect the central nervous system (brain and spinal cord) include herpesviruses, arboviruses, coxsackieviruses, echoviruses and enteroviruses. Some of these infections primarily affect the meninges (the tissues covering the brain and spinal cord) and the result of meningitis. Others affect primarily the brain and cause encephalitis. Infections that affect both the meninges and brain after a meningo-encephalitis. Meningitis is most common in children than is encephalitis.

The virus affects the central nervous system in two ways. They can directly infect and destroy cells of the central nervous system during acute illness. After recovery from an infection of the central nervous system or elsewhere in the body's immune response to infection sometimes causes secondary damage to cells that surrounds nerve. These secondary damage (postinfectious encephalomyelitis or acute disseminated encephalomyelitis) results in children having more symptoms weeks after recovery from acute illness.

 

Meningitis is usually caused by viruses. Viral meningitis is a self-limiting disease. Bacterial meningitis is much less common, but is a potentially fatal condition. Other organizations may be a rare cause meningitis, for example, spirochetes and fungi. Symptoms include fever, severe headache, neck stiffness and photophobia. Due to the severity of the condition, so it may be caused by a number of staff, fast and accurate diagnosis of the cause is essential for prompt initiation of appropriate treatment.

 

Fungal infections of the central nervous system (CNS) are increasingly diagnosed both in immunocompromised and immunocompetent persons. Sinocranial aspergillosis more frequently described from temperate countries, most often in otherwise immunocompetent individuals. The clinical syndromes as fungal infections of the central nervous system can present are protean and may involve most neuroaxis. Certain clinical syndromes are specific to certain fungal infections. The nose shape is the most common syndrome with zygomycosis and skull-base syndromes frequently in clinical syndromes in patients with aspergillosis sino-cranial. Sub-acute and chronic meningitis in patients infected with HIV are more likely to be due to cryptococcal infection. Early recognition of clinical syndromes in an appropriate clinical context, it is the first step towards full recovery in some of these infections. 

 

 

CONGENITAL INFECTIONS OF CENTRAL NERVOUS SYSTEM 

 

Although vaccines, new antimicrobial agents and improvement in hygiene practices, congenital infections remain a major cause of mortality and neurological morbidity in children long term worldwide. important players are Toxoplasma gondii, cytomegalovirus, Treponema pallidum, herpes simplex virus types 1 and 2, and rubella. In addition, several other agents, such as varicella-zoster, parvovirus B19, and Borrelia burgdorferi, which potentially can infect the fetus and result in the fetus. This paper provides an overview of these infectious disorders, and outlines current strategies for the treatment of acute and long-term treatment.

               

Infection

INFECTION AND INFECTIOUS DISEASE

ORGANISM INTERACTION AND SOURCES OF INFECTION

HOST / ORGANISM INTERACTIONS

Each of us is colonized with huge numbers of micro-organism ( bacteria plus viruses ,fungi , protozoa , and worms ) with which we coexist .The relationship with some of these organism is symbolic ,in which both partners benefit ,while others are commensals , living on the host without causing harm .Infection and illness may be due to these normally harmless commensals and symbiotes evading the body's defences and  penetrating into abnormal sites.Alternatively ,disease may be caused by exposure to exogenous pathogenic organism which are not part of our normal flora.



The symptoms and signs of infection are a result of the interaction between host and pathogen .in some cases ,such as the early stages of influenza ,symptoms are almost entirely due to killing of host cells by the invading organism .Usually ,however ,the harmful effects of infection are due to a combination of direct microbial pathogenicity ,and the body's response to infection .In meningococcal septicemia ,for example ,much of the tissue damage is caused by cytokines released in an attempt to fight the bacteria .In a few instances , such as chronic South American trypanosomiasis ( Chaga's disease ) ,mortality is almost entirely immunological ,with the parasite itself having little effect once the inflammatory process has been triggered .



SOURCES OF INFECTION

The endogenous skin and bowel commensals can cause disease in the host ,either because they have been transferred to an inappropriate site ( e.g bowel coliforms causing urinary tract infection ) ,or because host immunity has been attenuated ( e.g candidiasis in an immune compromised host ) .Many infections are acquired from other people ,who may be symptomatic themselves or be asymptomatic carriers .Some bacteria ,like the meningococcus ,are common transient commensals ,but cause invasive disease in a small minority of those colonized .Infection with other organisms ,such as the hepatitis B virus ,can be followed in some cases by an asymptomatic but potentially infectious carrier state.



Zoonoses are infections that can be trasmitted from wild or domestic animals to man .Infections can be acquired in a number of ways : direct contact with the animal ,ingestion of meat or animal products , contact with animal urine or faeces ,aerosol inhalation ,via an arthropod vector ,or by inoculation of saliva in a bite person to person .



Most microorganisms do not have a vertebrate or arthropod host but are free-living in the environment . The vast majority of these environmental organisms are non-pathogenic ,but a few can cause human disease.Person to person transmission of these infections is rare .Some parasites may have a stage of their life cycle which is environmental ( for example the free-living larval stage of Strongyloides stercoralis and the hookworms ) even though the adult worm requires a vertebrate host.Other pathogens can survive for periods in water or soil and may be transmitted from host to host via this route ,these should not be confused with true environmental organisms.



World -wide mortality from infectious disease such as :

• Acute lower respiratory infections
• HIV/AIDS.
• Diarrheal disease.
• Tuberculosis.
• Malaria.
• Measels.
• Tetanus.
• Whooping cough.
• Meningitis.
• Leishmaniasis.