Pneumonia pathogens

So-called atypical bacteria such as Chlamydia pneumoniae and Mycoplasma pneumoniae are the next most important group of community-acquired pneumonia pathogens, accounting for around one case in every eight in hospitalised patients. Atypical bacteria are not sensitive to beta-lactam antibiotics such as penicillins and cephalosporins and the treatment of choice is a macrolide such as erythromycin. 

In community-acquired pneumonia, pathogens responsible for infection include pneumococci, gram-negative rods, and atypicals such as M. pneumoniae and C. pneumoniae. Which one of the following drugs used as monotherapy is most likely to be both effective and safe, if your patient is pregnant ... 

Klebsiella pneumoniae subsp, aerogenes is found in the gut and respiratory tract of man and animals, and in soil and water. It may be distinguished from E. coli by a pattern of biochemical tests (Table 1.3). It can give rise to acute bronchopneumonia in humans but is not a common pathogen. 

Although viral infections are important causes of both otitis media and sinusitis, they are generally self-limiting. Bacterial infections m complicate viral illnesses, and are also primary causes of ear and sinus infections. Streptococcus pneumoniae and Haemophilus influenzae are the commonest bacterial pathogens. Amoxycillin is widely prescribed for these infections since it is microbiologically active, penetrates the middle ear, and sinuses, is well tolerated and has proved effective. 

The vast majority of conjunctivitis cases are viral in nature. For acute bacterial conjunctivitis, the cause is primarily grampositive organisms.11 The primary pathogens in acute bacterial conjunctivitis are Streptococcus pneumoniae, Staphylococcus aureus, or Haemophilus influenzae.12... 

Pathogens Streptococcus pneumoniae (most common), Haemophilus influenzae, Salmonella, Mycoplasma pneumoniae, Chlamydia, and viruses (parvovirus B1 9)... 

Recognizing the presumed site of infection and most common pathogens associated with the infectious source should guide antimicrobial choice, dose, and route of administration. For example, community-acquired pneumonia is caused most commonly by S. pneumoniae, E. coli is the primary cause of uncomplicated UTIs, and staphylococci and streptococci are implicated most frequently in skin and skin-structure infections (e.g., cellulitis). 

Bacterial meningitis is the most common cause of CNS infections. An epidemiologic review of bacterial meningitis in 1995 revealed that Streptococcus pneumoniae (pneumococcus) was the most common pathogen (47%), followed by Neisseria... 

List the common pathogens that cause community-acquired pneumonia, aspiration pneumonia, ventilator-associated pneumonia (early versus late onset), and health care-associated pneumonia. 

Streptococcus pneumoniae is the most common bacterial pathogen associated with community-acquired pneumonia. 

Empirical selection of antimicrobial therapy for ventilator-associated, health care-associated, and hospital-associated pneumonia is broad spectrum however, once culture and susceptibility information are available, the therapy should be narrowed (deescalation) to cover the identified pathogen(s). 

TABLE 68-1. Common Bacterial Pathogens by Type of Pneumonia... 

Pneumonia owing to aspiration of oral contents is caused by a variety of anaerobes (Bacteroides spp., Fusobacterium spp., Prevotella spp., and anaerobic gram-positive cocci), as well as Streptococcus spp. M. catarrhalis and Eikenella corrodens may be involved, but much less frequently.14,15 When gastric contents are aspirated, then enteric gram-negative bacilli and Staphylococcus aureus are more commonly the pathogens.15... 

The most common pathogens vary with the type of pneumonia, and they are listed in Table 68-1. M. pneumoniae lacks a cell wall therefore, 3-lactam drugs have no activity against... 

If a patient aspirates his or her oral contents and pneumonia develops, then anaerobes and Streptococcus spp. are the primary pathogens. Antibiotics active against these organisms include penicillin G, ampicillin/sulbactam, clindamycin, and metronidazole. 

---