Group B Streptoccal Bacteremia

Reviews here and here.

Also known as Streptococcus agalactiae, group B streptococcus is a pathogen that causes a variety of infectious syndromes. It colonizes the human GI tract and causes infection usually through a breach of the epithelial barriers.

In pregnant women it can cause choramnionitis and post-partum endometritis. In the neonate, it is a significant cause of neonatal sepsis and meningitis and this is why women are screened for carriage and given peri-partum antibiotics.

In the non-pregnant adult, it is commonly associated with:

• Bacteremia without focus (~40-50%)
• Skin/soft tissue infections (~20%)
  
• Pneumonia (~10-15%)
  
• Osteomyeltis or Septic Arthtitis (~10-15%)
• Other (Endocarditis, Peritonitis, Meningitis)
  

Diabetes is the most common underlying condition; however, other illnesses which likely pre-dispose to skin/soft tissue foci for bacterial entry including congestive heart failure is also a risk factor. Patients with underlying malignancy are also at increased risk.

Treatment includes a beta-lactam antibiotic (vancomycin in the penicillin allergic) pending sensitivities to other agents like the quinolones or clindamycin. GBS is universally penicillin sensitive at present. Source control is also important.

Staphylococcus Aureus Bacteremia

I direct you to previous posts here and here which discuss this entity. My often quoted articles including the ones on prognosis are available there. A new article on complications is available here.

This is a new review, which seems to be useful.

This article discusses the challenges of MRSA bacteremia. The challenges of MRSA are also covered here.

Adult Epiglotitis

Reviews here, here and JAMA case series here.

While the introduction of the Haemophilus influenzae type B vaccine has reduced the incidence in children, acute epiglotitis continues to occur in adults.

Patients present with sore throat, odynophagia , fever, dyspnea, drooling, dysphagia, foreign body sensation, and stridor.

Diagnosis can be made on the lateral neck radiograph (thumb-print sign) or on direct fiberoptic laryngoscopy.

The most common pathogens are oral flora including non-typable haemophilus species and group A streptococci. Treatment includes a third generation cephalosporin in association with close monitoring and airway management. Steroids (dexamethasone) are commonly used to decrease swelling, but the evidence for their use is actually limited.

About 40-50% will need invasive airway management (intubation, tracheostomy)

Catheter Related Bacteremia

Guidelines available here (excerpts below). Article on prevention here.

Diabetic Foot

Common presentation. Sometimes very difficult to treat. Would direct you to excellent guidelines here and to the JAMA Rational Clinical Exam Series here (related CID article here)

Dog Bite Infection

Good review on dog and cat bite infections here.


Prophylaxis: Amoxicillin-clavulinate or in penicillin allergic doxycycline + metronidazole (or clindamycin and moxifloxacin/levofloxacin).

Treatment of infection: Will require admission, surgical debridement with culture and broad spectrum antibiotics with gram negative and anerobic coverage (i.e. piperacillin-tazobactam, carbepenems, 3rd generation cephalosporin with metronidazole)

Pasturella multilocida, a gram-negative bacilli, is resistant to cephalexin and clindamycin. It is oxidase positve, indole positive, and won't grow well on MacConkey agar.

Capnocytophagia canismorsis, another fastidious gram negative rod is also oxidase and catalase positive. In patients with underlying immunodeficiency (splenectomy, cirrhosis, hypogammaglobulinemia) infections can progress to florid septic shock with multiorgan failure and DIC. It is hard to grow in the laboratory, and treatment should start early.

Vertebral Osteomyelitis

There is a review of osteomyelitis here with some images which I found useful below.

Because of the variety of causative organisms involved, a tissue diagnosis through bone biopsy is preferable to empiric treatment.

This article describes candidal vertebral osteomyelitis, which is also common in the IDU population and requires extended courses of treatment.