Miscellaneous Infections Flashcards
Presentation of bacterial vs fungal endophtlalmitis
Bacterial endophthalmitis usually presents acutely, often within days of an inciting event such as cataract surgery. Fungal endophthalmitis typically has a subacute presentation with symptoms worsening over days to weeks
Primary cause of endophthalmitis
Acute postcataract endophthalmitis is the major type of endophthalmitis seen worldwide. Most cases are bacterial, and approximately 75% present within 1 week
Primary pathogens in post-cataract endophtalmitis
negative. Of culture-positive cases, Gram-positive cocci comprise approximately 95% of isolates, with coagulase-negative staphylococci the primary pathogens (70% of cases) (35). Other pathogens include Staphylococcus aureus (10%), streptococci (9%), mixed Gram- positive bacteria (5%), and Gram-negative bacilli (6%)
Empiric therapy for postoperative endophthalmitis
cases. Both vancomycin and ceftazidime are injected empirically for suspected bacterial cases. In patients allergic to ceftazidime or cases known to be due to ceftazidime- resistant Gram-negative bacilli, amikacin may be injected instead of ceftazidime, al- though intravitreal aminoglyocosides are otherwise avoided because of the known but very rare complication of macular infarction.
Systemic antibiotics alone are not effective in treating bacterial endophthalmitis, and their value as adjunctive therapy (in addition to intravitreal antibiotics and vitrec- tomy) in postoperative and other types of exogenous bacterial endophthalmitis is unknown
Causes of keratitis-related endophthalmitis
Keratitis means corneal infection, and most cases are treated with topical anti- biotics. Progression to endophthalmitis is uncommon and usually occurs by exten- sion of the infection through the cornea into the aqueous. A majority of cases of keratitis-related endophthalmitis are due to molds.
0.5% progressed to endophthalmitis; fungal keratitis (keratomycosis) was a significant risk factor for such progression (62). Over half the endophthalmitis cases in that series were due to molds (53%), while Gram-positive bacteria (27%) and Gram-negative bacilli (20%) comprised the re- maining cases
Endogenous endophthalmitis natural history and presentation
Endogenous endophthalmitis, which results from bacteremic or fungemic seed- ing of the eye, is rare. Only 5 to 15% of all endophthalmitis cases are endogenous (66). The choroid is usually seeded first since it is highly vascular, and as a consequence the intraocular infection usually starts in the posterior segment. Bacterial cases typically present acutely and fungal cases subacutely.
Only half of the patients with endogenous endophthalmitis in one series had symptoms of an underlying infection on presentation, and only 75% had positive blood cultures
Infections commonly associated with endogenous endophthalmitis include liver abscess, endocarditis, and urinary tract infection
management of candida endophthalmitis
Treatment with systemic agents is usually adequate for cases of chorioretinitis that do not have macula-threatening lesions. Macula-threatening chorioretinitis and cases of endophthalmitis require intravitreal antifungal injec- tions (amphotericin or voriconazole) in addition to systemic therapy
fluconazole is recommended for fluconazole-susceptible Candida, voricona- zole for fluconazole-resistant but voriconazole-susceptible isolates, and liposomal amphotericin, with or without 5-flucytosine, for azole-resistant strains.
eyes. Systemic echinocandins do not reach adequate concentrations in the vitreous to treat endophthalmitis. Echinocandins may achieve reasonable levels in the choroid, but their role in treating chorioretinitis alone is unknown because there are few data in humans.
Targets for stool testing in diarrhea in immune competent patients
People with fever or bloody diarrhea should be evaluated for enteropathogens for which antimicrobial agents may confer clinical benefit, including Salmonella enterica sub- species, Shigella, and Campylobacter (strong, low).
Agents of persistent diarrhea in HIV/AIDS
People with acquired immune deficiency syn- drome (AIDS) with persistent diarrhea should undergo additional testing for other organisms including, but not limited to, Cryptosporidium, Cyclospora, Cystoisospora, microsporidia, Mycobacterium avium complex, and cyto- megalovirus (strong, moderate).
Recommendations for empiric antimicrobials therapy in immunocompetent patients with bloody diarrhea
In immunocompetent children and adults, empiric anti- microbial therapy for bloody diarrhea while waiting for results of investigations is not recommended (strong, low), except for the following:
Infants <3months of age with suspicion of a bacterial etiology.
Ill immunocompetent people with fever documented in a medical setting, abdominal pain, bloody diar- rhea, and bacillary dysentery (frequent scant bloody stools, fever, abdominal cramps, tenesmus) presump- tively due to Shigella
People who have recently travelled internation- ally with body temperatures ≥38.5°C and/or signs of sepsis (weak, low).
Empiric antimicrobials therapy recommendations for immunocomptetent patients with watery diarrhea
In most people with acute watery diarrhea and without recent international travel, empiric antimicrobial therapy is not rec- ommended (strong, low). An exception may be made in people who are immunocompromised or young infants who are ill-ap- pearing. Empiric treatment should be avoided in people with persistent watery diarrhea lasting 14days or more (strong, low
Recommended regimens for empiric treatment of bloody diarrhea
empiric antimicrobial therapy in adults should be either a fluoroquinolone such as ciprofloxacin, or azithro- mycin, depending on the local susceptibility patterns and travel history
Empiric therapy for chil- dren includes a third-generation cephalosporin for infants <3months of age and others with neurologic involvement, or azithromycin, depending on local susceptibility pat- terns and travel history
