-SCHASHA-

Usage of Antibiotics in the Wards

1. 63/Malay/Male ; U/L DM 

    P/w : right sided headache and ear lobe pain x 3/7 and fever x 2/7

    Dx : Right neck cellulitis secondary to uncontrolled DM

    Abx : IV Ampicillin-Sulbactam (Unasyn) 1.5 g TDS 

   

    Discussion: 

Ampicillin is a penicillin which exerts its actions by inhibiting the synthesis of bacterial cell wall (bactericidal) while Sulbactam is an irreversible inhibitor of many beta-lactamases that occur in penicillin-resistant organisms. When coupled together, Sulbactam enhances the effect of Ampicillin. Unasyn has shown to make resistant strains more susceptible to the combination of the drugs than to the beta-lactam antibiotic alone. Unasyn has an effect of a wide range of both Gram +ve and –ve bacteria such as Staph. aureus or epidermidis, S pneumoniae, H. influenzae along with many penicillin-resistant or methicillin-resistant strains .

This antibiotic was appropriately given to this patient with cellulitis which often sees Streptococci species as the most common offending organism.  In some cases of cellulitis that may be complicated with abscesses, it is often safer to cover these patients with antibiotics that work against a wide range of bacteria. Unasyn allows a better coverage by increasing the antimicrobial spectrum.

2. 73/Malay/Male ; K/C/O Left cerebral pontine angle tumour with post craniotomy & post tracheostomy

    P/w : pain at tracheostomy site x 1/7 and productive cough x 2/7 (greenish, foul smelling sputum)

    Ix : Sputum C&S – Pseudomonas sp.

    Dx : Bronchopneumonia secondary to infected tracheostomy site

    Abx : IV Cefepime 2g BD

    Discussion: 

Cefepime is a 4^th generation cephalosporin that exerts bactericidal effects against Gram –ve bacteria such as E. coli, Klebsiella sp., Pseudomonas sp. and Enterobacter sp. Gram +ve species that are susceptible are Staph. aureus, Strep. pneumoniae or Strep. pyogenes.

Cefepime is a good choice for an aerobic bacteria such as Psedumonas sp. as it exerts rapid penetration into the cell walls of Gram –ve bacterial walls. Cefepime has proven effectiveness against moderate to severe pneumonias caused by such an microorganism.

3. 50/Malay/Male ; U/L DM 

    P/w : Right sided chest pain x 2/7 with SOB and productive cough x 2/7

    Ix : Sputum cuture - H. influenzae

    Dx : Sepsis secondary to lung empyema

    Abx : IV Ceftriaxone 2g BD

    Discussion: 

Ceftriaxone is a 3^rd generation cephalosporin exhibits bactericidal activity against the synthesis of cell walls. It is highly effective against Gram –ve bacteria that are resistant against other beta-lactam antibiotics. Example of organisms are Klebsiella sp. Haemophilus sp. or Neisseria sp.

This is an appropriate choice of antibiotic as septicaemia should be treated with broad-spectrum antibiotics. Ceftriaxone is known to have increased potency against Gram –ve microorganisms and it is stable against the hydrolysis of many beta-lactamases (including penicillinases and cephalosporinases).

4. 71/Chinese/Female ; U/L Bronchial asthma & HPT

    P/w: SOB and productive cough x 1/7

    Dx: Bronchospasm secondary to CAP

    Abx: IV Ceftriaxone 2g OD 

    Discussion: 

In patients with community-acquired pneumonia, common causative organisms are Strep. penumoniae (penicillin-sensitive/resistant strains), Haemophilus influenzae (ampicillin-sensitive/resistant strains), and M. catarrhalis. Patients with uncomplicated CAP can be given Ceftriaxone either alone or with a combination with a macrolide such as Azithromycin. As discussed earlier, Ceftriaxone has strong activity against H. Influenza. It also works well against Strep. Pneumoniae, M. catarrhalis which are seen in CAP. Its once-daily regime allows the avoidance of otherwise complex hospital regimes for the treatment of CAP. When it combination with a macrolide-containing antibiotic, it has shown to have a better outcome for CAP patients.

Ceftriaxone is a good choice for this patient with CAP. With that said, another acceptable choice could be a fluoroquinolone such as Moxifloxacin which shows activity against penicillin- and macrolide-resistant strains of S. pneumoniae and beta-lactamase-producing Haemophilus.

5. 56/Malay/Female ; U/L DM, HPT, IHD, ESRF

    P/w : SOB x 3/7

    Ix : Pleural fluid analysis- Gram +ve cocci

    Dx : Right sided pleural effusion secondary to CAP 

    Abx : IV Ampicillin-Sulbactam (Unasyn) 1.5g OD

    Discussion: 

Unasyn as discussed above, covers a wide range of both Gram +ve and Gram –ve bacteria. It is a good choice of antibiotic as the occurrence of penicillin-resistant strains of organisms is becoming more common. A combination of Ampicillin and Sulbactam will provide a wider antibacterial coverage.

6. 70/Malay/Female ; U/L DM, HPT, post-APR for lower rectal tumour

    P/w : Generalized body weakness + lethargy x 1/7 and pain upon urination 

    Ix : UFEME - nitrites and leucoyctes, blood glucose: 2.3mmol/L

    Dx : Hypoglycemia due to poor oral intake & UTI

    Abx : IV Cefuroxime 1.5g TDS

    Discussion: 

UTI is most commonly caused by Gram –ve organisms such as E. coli. Cefuroxime, a 2^nd generation of cephalosporin works actively against these organisms by inhibiting the synthesis of the cell walls.

It is an appropriate choice of antibiotic although there are other choices such as Trimethoprim-Sulfamethoxazole (Bactrim) or a fluoroquinolone like Ciprofloxacin.

7. 41/Indonesian/Male ; No known medical illnesses

    P/w : vomiting x 1/7 (10 times) associated with fever x 2/7

    Ix : UFEME - leucocytes and nitrites

    Dx : AGE and UTI

    Abx : IV Ampicillin-Sulbactam (Unasyn) 1.5g TDS

    Discussion: 

Unasyn can be used in uncomplicated UTI that is most often caused by Gram –ve microbes. However, UTI in men should not be disregarded and recurrent UTI ought to be investigated. Most AGE are viral in origin and self-limiting, hence the antibiotic may not impose any benefits.

8. 56/Malay/Female ; U/L ESRF, DM, HPT

    P/w: SOB x 2/7, associated with productive cough x 2/7 and fever x 1/7 

    Ix: CXR - pneumonic changes, pleural fluid analysis - exudative features +     Gram positive cocci

    Dx: Right sided pleural effusion secondary to CAP

    Abx: IV Amoxicillin-Clavulanate (Augmentin) 1g OD and T. EES 800mg BD

    Discussion: 

Augmentin is an antibiotic with a broad coverage of antimicrobial activity due to its combination of Amoxicillin and Clavulanate. Clavulanate on its own has little atibacterial activity as a beta-lactamase inhibitor. But, together with Amoxillin, it possesses a syngergistic effect. It anticipates the resistance of organisms towards Amoxicillin thus, improving bactericidal activity. Hence, it covers both Gram +ve and Gram –ve organisms. Erythromycin works effectively against Gram +ve and Gram –ve bacteria.

In this case, it is appropriate to use a combination of Augmentin and EES, as to provide the patient with good coverage to clear off the respiratory infection that has caused the complication of pleural effusion.

9. 76/Malay/Female ; U/L HPT, OA, UV prolapse, COAD

    P/w : Productive cough x 2/7 (yellowish), associated with fever and SOB x 1/7

    Ix : CXR - left lower zone air bronchogram, UFEME - leucocytes, nitrites 

    Dx : CAP and UTI 

    Abx : IV Azithromycin 500mg OD and IV Amoxicillin-Clavulanate (Augmentin) 1.2g TDS

    Discussion: 

As mentioned above, Augmentin is clinically active against a wide range of Gram +ve and Gram –ve bacteria. Azithromycin, works on both Gram +ve and Gram –ve bacteria but has a stronger effect against Gram –ve organisms.

Since UTI is often caused by Gram –ve bacteria and CAP can be caused by both Gram +ve and Gram –ve microbes, this is an appropriate choice of antibiotic as it provides coverage for both infections.

10. 69/Malay/Female ; U/L HPT, Bronchial asthma

      P/w : SOB x 1/7, Fever x 3/7, cough x 1/52

      Ix : CXR - pneumonic changes, WBC - neutrophilic leucocytosis

      Dx : AEBA secondary to CAP

      Abx : IV Amoxicillin-Clavulanate (Augmentin) 1g TDS and T. EES 800mg BD 

       Discussion:  

Augmentin is usually effective against beta-lactamases producing strains such as S. pneumoniae, M. Catarrhalis and H. Influenza which are common organisms in CAP. EES as mentioned works effectively against organisms such as Corynebacterim, Gram +ve cocci, M. pneumoniae and Gram –ve microbes.

A combination of both these antibiotics is appropriate to cover both Gram +ve and –ve organisms commonly found in CAP.