BACTERIAL INFECTIONS PART II

1. BACTERIAL INFECTIONSPART II Andrew’s P 330 – 45,821 (p 330 – 357)

3. Gas gangrene(clostridial myonecrosis) • Most severe form of infectious gangrene • Develops in deep lacerated wounds of muscle tissue • Incubation only a few hours • Sudden onset characterized by a chill, rise in temp, marked prostration and severe local pain • Gas bubbles cause crepitation

4. Gas gangrene(clostridial myonecrosis) • Mousy odor is characteristic • Caused by a variety of species of the genus Clostridium • Most frequently C. perfringens, C. oedematiens, C. septicum, and C. haemolyticum • A subacute variety occurs – peptostreptococcus • Clinically similar but with a delayed onset

5. treatment • Treatment of all clostridial infections is wide surgical debridement and intensive antibiotic therapy • Hyperbaric oxygen therapy may be of value if immediately available

6. Chronic undermining burrowing ulcers • Meleney’s gangrene • Described as a postoperative progressive bacterial synergetic gangrene • Usually follows drainage of peritoneal abscess, lung abscess, or chronic empyema • Three skin zones – outer bright red; middle, dusky purple; and inner, gangrenous with a central area of granulation tissue • Pain is excruciating

7. Chronic undermining burrowing ulcers • The essential organism is a microaerophilic, nonhemolytic streptococcus in the spreading periphery of the lesion , associated with S. aureus or Enterobacteraceae in the zone of gangrene • Wide excision and grafting are primary therapy • Antimicrobial agents, pcn, and an aminoglycoside should be given as adjunctive therapy

8. Fournier’s gangrene of the penis or scrotum • A malignant gangrenous infection of the penis, scrotum, or perineum • May be due to an infection with group A strep or a mixed infection with enteric bacilli and anaerobes • Usually considered a form of necrotizing fasciitis • Aerobic and anaerobic culture • Appropriate antibiotics, sx debridement

9. Infections caused by gram-negative organisms

10. PSEUDOMONAS INFECTIONSecthyma ganrenosum • In the gravely ill patient opalescent, tense vesicles or pustules surrounded by narrow pink to violaceous halos • Quickly become hemorrhagic and rupture to become round ulcers with necrotic black centers • Usually seen on the buttocks and extremities

11. ecthyma ganrenosum • Occurs in debilitated persons who may be suffering from leukemia, in the severely burned patient, in pancytopenia or neutropenia, functional neutrophilic defect, terminal carcinoma, and other severe chronic disease • Healthy infants in the diaper area, on abx • Classic vesicle should suggest the diagnosis

12. ecthyma ganrenosum • Contents will show gram-negative bacilli • Culture grows Pseudomonas aeruginosa • Treatment with immediate institution of IV anti-Pseudomonals • And aminoglycoside in combination with antipseudomonal penicillin

14. Green nail syndrome • Characterized by onycholysis of the distal portion of the nail and a striking greenish discoloration • Frequently associated with paronychia in persons whose hands are often in water • 1% acetic acid solution soaks • Neosporin solution

15. Gram-negative toe web infection • Often begins with dermatophytosis • Dermatophytosis complex – where many types of gram-negative organisms may be recovered, and as the inflammation and maceration progress, it is less often possible to culture dermatophytes • Prolonged emersion may lead to overgrowth

16. treatment • Topical antifungals • With progression of disease – topical antibiotics and acetic acid compresses • Systemic antibiotics in full blown infection

17. Blastomycosis-like pyoderma • Large verrucous plaques with elevated borders and multiple pustules may occur as a chronic vegetating infection • Most patients have underlying systemic or local host compromise • P. aeruginosa, S. aureus, Proteus, E. coli or streptococci may be isolated • Cipro 500 mg bid

18. Pseudomonas aeruginosa-folliculitis • Hot tub folliculitis • Characterized by pruritic, follicular, maculopapular, vesicular, or pustular lesions • Occurs 1-4 days after swimming in a hot tub, whirlpool, or public swimming pool • Most lesion occur on the side of the trunk, axillae, buttocks, and proximal extremities

19. Associated complaints may include earache, sore throat, headache, fever, malaise • Typically involutes within 7-14 days without therapy, prolonged episodes have been reported • Third generation oral cephalosporin or a fluoroquinalone • Prevention measures include water filtration, chlorination, maintenance of water, and frequent changing

20. External otitis • Swelling, maceration and pain may be present • In up to 70% of cases P. aeruginosa may be cultured • Especially common in swimmers • Local applications of antipseudomonal Cortisporin Otic Solution • Post op external otitis

22. External otitis • Malignant external otitis • Occurs in elderly patient with diabetes • Swelling, erythema and pain are more pronounced, with purulence and a foul odor • Facial nerve palsy develops in 30% of the cases • Cartilage necrosis may occur • May be life threatening • Appropriate systemic antibiotics

23. Gram-negative folliculitis • Usually due to Enterobacteraceae, Klebsiella, Escherichia, Proteus, or Serratia • Occasional cases caused by Pseudomonas

24. malacoplakia • Rare granuloma, originally reported only in the genitourinary tract of immunosuppressed renal transplant recipients • May also occur in the skin an the subcutaneous tissues of other patients with deficient immune responsiveness (HIV) • Patients are unable to resist infections with S. aureus, P. aeruginosa and E. coli

25. malacoplakia • Granulomas may arise as yellowish red papules in the natal cleft, as draining sinuses in the vicinity of the urethra, as perianal ulcers, , as a painful draining abscess on the thigh, or as a lesion on the vulva • Treatment depends on the isolated organism • Fluoroquinalones are usually useful

26. Haemophilus infuenzae cellulitis • Haemophilus infuenzae type B a distinctive bluish or purplish red cellulitis of the face accompanied by fever in children below age 2 • Bacteremia may result – meningitis, orbital cellulitis, osteomyelitis, or pyarthrosis • Antibiotic therapy • Vaccine available, given at 2, 4, and 6 months

27. chancroid • An infectious, contagious, ulcerative, sexually transmitted disease • Haemophilus ducreyi gm- bacillus • One or more deep or superficial tender ulcers on the genitalia and painful adenitis in 50% • Men > women

28. chancroid • Begins as an inflammatory macule or pustule 1-5 days after intercourse • Generally appears on the distal penis or perianal area in men • On the vulva, cervix, or perianal area in women • Extragenital infections have been reported • Autoinnoculation forms “kissing-lesions”

30. chancroid • Pustules rupture and ulcers form • These bleed easily and are very tender • the lymphadenitis of chancroid is mostly unilateral, tender and may rupture spontaneoulsy • Culture for definitive diagnosis and sensitivity testing

31. chancroid • The selective medium contains vancomycin • Smears are only diagnostic in 50 % • A combined PCR technique allows for the diagnosis of syphilis, herpes simplex, and chancroid form a single swab • The diagnosis of chancroid does not rule out syphilis • Repeat serologic testing and HIV is rec. • Chancroidal genital ulcer disease facilitates the transmission of HIV infection

32. treatment • Treatment of choice is azithromycin 1 gm orally as a single dose • Partners with contact less than ten days out should also be treated

33. Granuloma inguinale(granuloma venereum, Donovanosis) • A mildly contagious, chronic, granulomatous, locally destructive disease • Characterized by progressive, indolent, serpiginous ulcerations of the groin, pubes, genitalia and anus • Begins as single or multiple subcutaneous, nodules, which erode through the skin to produce, clean, sharply defined lesions, which are usually painless

34. Granuloma inguinale(granuloma venereum, Donovanosis) • More than 80% of cases demonstrate hypertrophic, vegetative granulation tissue, which is soft, has a beefy-red appearance, and bleeds readily • Genitalia are involved in 90% of cases, inguinal region 10% • Most commonly occur on the prepuce or glans in men, and on the labia in women

36. Granuloma inguinale(granuloma venereum, Donovanosis) • Incubation period is unknown, 8-80 days, 2-3 weeks most common • Persisting sinuses and hypertrophic scars, devoid of pigment are characteristic of the disease • Regional lymph nodes are usually not enlarged • Lesions are not painful and produce only mild subjective symptoms

37. Granuloma inguinale(granuloma venereum, Donovanosis) • Pseudoelephantiasis may occur with blockage of lymph channels • Dissemination from the inguinal region may be by hematogenous or lymphatic routes • Calymmatobacterium granulomatis • The exact mode or transmission of infection is undetermined

38. Granuloma inguinale(granuloma venereum, Donovanosis) • The role of sexual transmission is controversial • Giemsa or silver stains for Donovan bodies • May coexist with syphilis • Test for HIV • Trimethoprim-sulfamethoxazole • Doxycycline • Therapy continues until all lesions have healed

39. Gonococcal dermatitis • Primary gonococcal dermatitis is a rare infection that occurs mostly as erosions that may be 2 - 20 mm • Has been reported on the median raphe without urethritis, as extragenital gonococcal ecthyma, simulating herpetic whitlow, and as scalp abscesses in infants secondary to direct fetal monitoring • cipro

40. gonococcemia • Characterized by a hemorrhagic vesiculopustular eruption, bouts of fever, and arthralgia or acute arthritis of one or several joints • Lesions begin as tiny erythematous papules • Evolve into vesiculopustules on a deeply erythematous base or a purpuric macule • The purpuric lesions occur acrally, mostly on the palms and soles and over joints

41. gonococcemia • Fever, chills, malaise, migratory polyarthralgia, myalgia, and tenosynovitis may accompany lesions • Lesions are usually tender and sparse, and occur principally over the extremities • Involution in about 4 days • Many patients seen are women with asymptomatic anogenital infections in whom dissemination occurs during pregnancy or menstruation

44. gonococcemia • In severe or recurrent cases compliment deficiency should be investigated, esp. C5, C6, C7 or C8 • Neisseria gonorrhoeae • Organisms may be seen in early skin lesions, blood, GU tract, and joints • TOC ceftriaxone IV I gm daily for 24 – 48 hours after improvement begins, then switching to PO for another week of TX

45. meningococcemia • Presents with fever, chills, hypotension, and meningitis • About ½ - 2/3 of patients develop a petechial eruption , most frequently on the trunk and lower extremities • This may progress to ecchymosis, bullous hemorrhagic lesions, and ischemic necrosis • Oral and conjunctival mucous membranes may also be affected

46. meningococcemia • Primarily affects young children • Males more frequently than females • Inherited or acquired deficiencies of the terminal components of compliment or properdin are predisposed to infection • Chronic meningococcemia is a rare variant, seen typically in young adults

47. Neisseria meningitides, gm – diplococcus • Human nasopharynx is the only known reservoir • Carriage rates = 5 – 10 % • TX, PCN G • Chloramphenicol if pcn allergy • Household members, and day-care and close school contacts should receive prophylactic therapy • Vaccine available for high risk groups

48. Vibrio vulnificus infection • Vibrio vulnificus, gm – rod • Infection produces a rapidly expanding cellulitis or septicemia in those exposed • May be acquired via the GI tract, after eating raw oysters or other seafood • Localized skin infection may occur following exposure of an open wound to sea water

49. Tabasco kills Vibrio, right?

50. Vibrio vulnificus infection • Skin lesions begin within 24-48 hrs following exposure • Localized tenderness, erythema, edema, and indurated plaques are seen in 90% of pts • Most common on the lower extremities • If the skin is invaded primarily, septicemia may not occur, however with progressive lesions amputation may be required • Mortality with septicemia is > 50%