Antibiotic Therapy Study Notes

Tigecycline is an intravenous antibiotic that effectively targets MRSA and anaerobic bacteria, making it particularly useful for treating infections like abscesses and empyemas, which are often walled-off and difficult for the immune system to combat.

Quinolones are the only oral antibiotics effective against Pseudomonas.

Quinolones are known for their excellent lung penetration, making them valuable for treating respiratory infections like pneumonia, bronchitis, and COPD exacerbations.

Quinolones, especially when used in combination with steroids, can increase the risk of tendon rupture, particularly in elderly patients.

The combination of quinolones and steroids in elderly patients, especially for COPD treatment, poses a significant risk of tendon rupture.

Clinicians should always be mindful of the potential for tendon rupture when prescribing quinolones, especially when used with steroids in elderly patients.

The combination of quinolones and steroids in elderly patients can lead to tendon rupture, a potentially serious side effect that clinicians must be aware of.

Oral or intravenous (IV) steroids increase the risk of tendon rupture when combined with quinolones, but inhaled steroids are considered safe.

Levaquin is most effective against Gram-positive bacteria, especially Streptococcus pneumoniae, a common cause of pneumonia.

Ciprofloxacin (Cipro) is better against Gram-negative bacteria than Gram-positive. It's particularly effective against Pseudomonas aeruginosa.

Moxifloxacin (Moxi) has limited anaerobic coverage which makes it less desirable. It also has poor urinary concentration, so it's not suitable for UTIs.

Erythromycin, a macrolide antibiotic, was initially used for bacterial infections but is now primarily used for its GI motility properties, causing diarrhea.

Azithromycin, a modified erythromycin, effectively treats atypical bacterial infections without the severe diarrheal side effects.

Carbapenems are broad-spectrum antibiotics used in hospitals for serious infections caused by resistant bacteria, including those producing ESBLs.

Carbapenems interact with valproic acid (an anti-seizure medication), significantly decreasing its levels and potentially causing seizures. Increasing valproic acid dose does not compensate for this interaction.

Imipenem (Primaxin) was the first carbapenem but had a high incidence of seizures. Meropenem, a modified version, has a similar spectrum but lower seizure risk.

Antibiotics that effectively treat a wide range of bacteria, often used initially when the specific cause of infection is unknown.

A bacterial infection of the blood that can lead to organ failure and death. Symptoms include fever, low blood pressure, and respiratory distress.

The process of determining which antibiotic is most effective against a specific bacterial infection.

Antibiotics that kill bacteria by reaching a certain concentration in the body. Their effectiveness depends on achieving a high peak level.

Antibiotics that kill bacteria by maintaining a certain concentration above the minimum inhibitory concentration (MIC) for a specific time.

A group of antibiotics that are effective against Gram-negative bacteria, but not Gram-positive bacteria. They are often used in combination with other antibiotics for endocarditis.

A monobactam antibiotic that effectively targets Gram-negative bacteria. It is a good alternative for patients with penicillin allergies.

Aminoglycosides have fallen out of favor due to their complex dosing requirements, potential for kidney damage (nephrotoxicity), and narrow therapeutic window.

A type of bacteria that has become resistant to methicillin and other similar antibiotics. Commonly known as MRSA.

Antibiotics that target and effectively eliminate Gram-positive bacteria. Examples include vancomycin and linezolid.

Combining vancomycin and gentamicin is not recommended because they can both cause kidney damage (synergistic nephrotoxicity), leading to an increased risk of acute kidney injury.

A potent antibiotic that has maintained its effectiveness against MRSA since its introduction. It has good oral availability, but can be expensive.

An antibiotic known for its good oral availability and effectiveness against MRSA. Although initially expensive, its price has decreased over time.

Linezolid can interact with certain antidepressants like SSRIs (selective serotonin reuptake inhibitors) which increases the risk of a serious condition known as serotonin syndrome.

Oral vancomycin is the first-line treatment for C. difficile infection (C. diff). Intravenous vancomycin is used to treat systemic infections.

Oral vancomycin has become the first-line treatment for C. difficile infections, replacing metronidazole (Flagyl) which was previously used.

The slide highlights the antibiotic coverage for different bacterial groups (Gram-positives, Gram-negatives, anaerobes, atypicals, and specific organisms like MRSA and Pseudomonas). Bars represent antibiotic effectiveness; longer bars indicate broader coverage.

Carbapenems like meropenem are broad-spectrum antibiotics with a wide coverage across different bacterial groups.

Beta-lactamase inhibitors like avibactam, tazobactam, and vaborbactam are added to some antibiotics to enhance their effectiveness against bacteria that produce beta-lactamases, enzymes that normally inactivate these antibiotics. These combinations are used for multidrug-resistant infections.

The 'superbugs' discussed refer to multidrug-resistant strains of bacteria that are difficult to treat due to their unusual resistance mechanisms. These infections often require specialized antibiotic combinations like those containing beta-lactamase inhibitors.

CRE (Carbapenem-resistant Enterobacteriaceae) is a group of bacteria particularly resistant to carbapenems. Vabomere (meropenem plus vaborbactam) is used for CRE infections due to its extended spectrum coverage.

Anaerobacter ACA is a specific group of Gram-negative bacteria known for their high resistance levels, often displaying multiple resistance markers (R) in cultures. They are challenging to treat but there are options available.

KPC bacteria produce an enzyme that breaks down carbapenems, rendering those antibiotics ineffective. This requires using alternative therapies like those with beta-lactamase inhibitors.

Pseudomonas is often resistant to many antibiotics, with some strains exhibiting even higher resistance levels, requiring specialized treatment options like those including beta-lactamase inhibitors.

Ceftazidime-avibactam (Avycaz), ceftolozane-tazobactam (Zerbaxa), and meropenem-vaborbactam (Vabomere) are newer antibiotic combinations used against multidrug-resistant infections. They are considered 'super drugs' because of their exceptional effectiveness against very resistant strains.