Line associated infections and bacteraemia

1. Line associated infections and bacteraemia Dr. Brian O’Connell

2. Adapted from Bone et al. Chest 1992; 101: 1644-55

3. Gram negative cell wall

4. Diagram of a Gram-positive bacterial cell-wall

5. Microbial triggers of sepsis • Bacteraemia/fungaemia • Positive blood cultures are more common the more severe the disease • More likely to have positive blood cultures in patients with septic shock • Severe local infections associated with greater mortality • Endotoxaemia – lipopolysaccharide • Other bacterial toxins • Bacterial superantigens (e.g. TSST-1, streptococcal pyrogenic exotoxins)

6. Diagnosis of Sepsis • No bedside or laboratory test provides a definitive diagnosis • Clinical evidence of SIRS (tachycardia, tachypnea, leucocytosis, fever) with altered mental status, hyperbilirubinaemia, acidosis, thrombocytopenia • Non-infective causes include: • Burns, pancreatitis, trauma, adrenal insufficiency, malignant hyperthermia, heat-stroke, hypersensitivity reactions)

8. Bacteraemia/Blood-stream Infection (BSI) • Primary • cause majority of hospital-acquired BSI (64%) • most are due to infected intravascular catheters • remainder have bacteraemia with no identifiable source • Secondary • Secondary infections are related to severe infections at other sites, such as the urinary tract, lung, postoperative wounds, and skin. • Cause the majority of community-acquired BSI

9. Patterns of bacteraemia 3 patterns of bacteraemia • Transient • Lasts minutes to hours • Instrumentation of contaminated mucosal surface • Tooth brushing, dental procedures, cystoscopy • manipulation of infected tissue • Intermittent • Usually from un-drained infection • Continuous • Usually from an endovascular infection • Endocarditis, infected aneurysm,

10. Diagnosis of bacteraemia • Blood culture • Take two sets from different sites • Should be performed on all hospitalised patients with fever (≥38ºC) combined with leucocytosis or leucopaenia before the use of parenteral or systemic antimicrobial therapy • Systemic and localized infections including suspected acute sepsis, meningitis, osteomyelitis, arthritis, acute untreated bacterial pneumonia, or fever of unknown origin in which abscess or other bacterial infection is suspected or possible

12. Taking a blood culture from a central line Taking a blood culture from a Peripheral vein

13. Blood cultures Take at least 10 ml per set

14. What are the most common organisms recovered from blood?

15. Different groups of patients Traditional divisions :2 broad groups hospital acquired community acquired New divisions:3 groups Hospital acquired Health-care association Non health-care association / Unknown

16. Definitions • Hospital acquired (HA): • isolate recovered from inpatient > 48 h in hospital • Health care associated (HCA): • isolate recovered from patient with one of the following risk factors • inpatient in SJH in previous 90 days • outpatient in SJH in previous 30 days • referred or transferred from another hospital • resident in nursing home • Non Hospital or Healthcare associated (NHCA): • isolate from patient not defined as HA or HCA

17. Top 5 Bacteraemia isolates in SJH during 2006

18. Micro-organisms causing bacteraemia • Overall change from predominantly Gram-negative infection to Gram-positive infection

19. Single organism bacteraemias in EORTC trials of febrile neutropenia

20. What are the common sources of blood-stream infection? • Hospital-acquired • Central line • Urinary tract • Intra-abdominal • Community-acquired • Urinary tract • Intra-abdominal • Respiratory tract

21. Management • Antimicrobial therapy • Early appropriate antimicrobial therapy improves survival • Surgical drainage • Important to look for and drain sources of infection • IV- fluids, blood transfusion, pressors • Nutrition • Other possible therapies • Steroids • vasopressin • Anti-inflammatory drugs • Anticoagulants

22. Empiric antimicrobial therapy • choice depends upon institutional spectrum of infections, susceptibility pattern of infecting micro-organisms and individual clinical situation

23. Catheter-related infections • Intravascular catheters are indispensable in modern-day medical practice • Infections associated with intravascular catheters are a major cause of morbidity & mortality

26. Infectious complications of central venous catheters (CVCs) • Local site infection • Catheter-related blood stream infection (CRBSI) • Septic thrombophlebitis • Endocarditis • Metastatic infection – e.g. endocarditis, lung abscess, brain abscess, osteomyelitis & endopthalmitis

27. Appearance of a central venous catheter associated with bacteraemia. Note the minimal surrounding erythema and purulence at the insertion site

28. Incidence of catheter-related infection varies:- • Type of catheter - non-tunnelled vs. tunnelled • Site of catheter – int. jugular > subclavian • Number of catheter days • Frequency of catheter manipulation • Setting of catheter placement i.e. emergency/elective

29. Incidence of catheter-related infection varies: • Hospital size • Hospital service/unit • Patient-related factors e.g. underlying disease and acuity of illness

30. Pathogenesis of catheter-related blood-stream infection

31. Scanning electron micrograph of a Staphylococcus biofilm. Emerging Infectious Diseases 2001; 7: 277-281

32. Epidemiology • In the U.S., 15 million catheter days occur in ICUs each year • Average rate of catheter associated bacteraemias is 5.2 per 1,000 catheter days • So, approximately 78,000 catheter associated infections occur in ICUs in the US each year • 250,000 cases annually if entire hospitals assessed rather than exclusively ICUs

33. Consequences • Significant increase in patient morbidity & mortality • Significant increase in hospital costs • Significant increase in duration of hospitalisation

34. Morbidity & Mortality Meta-analysis of 2573 CRBSIs • Case fatality rate – 14% • Directly attributable to CVC – 19% • Mortality rate highest for S. aureus bacteraemia – 8.2% overall

35. Cost • In ICU studies, cost per infection is an estimated $34,500 - $56,000 • Annual cost of caring for patients with CRBSIs estimated at up to $2.3 billion

36. Common pathogens isolated in CRBSIs

37. Catheter-Related Blood stream infection (CRBSI)Definition Essential Criteria: Peripheral blood culture positive Clinical signs and symptoms of infection (Temp>=38ºC or rigors/chills or hypotension) No other obvious source of sepsis And one of the following: 1. 15 CFU on line tip 2. > 2 h differential time to positivity (Central vs. Peripheral) Guidelines for prevention of Intra-vascular Catheter Related infections MMWR August 9,2002/Vol.51/No.RR-10

38. Management of Catheter-related blood-stream infection Tunnelled CVC-related blood stream infection Complicated infection Septic thrombosis, endocarditis, osteomyelitis Tunnel infection or port abscess Remove CVC/ID & treat with antibiotics for 4 – 6 weeks, 6 – 8 weeks for osteomyelitis Remove CVC/ID & treat with antibiotics for10–14 days

39. Tunnelled CVC-related blood stream infection Uncomplicated infection Coagulase negative Staphylococcus S. aureus • Remove CVC & use systemic antibiotic for 14 days if TOE –ve • For CVC salvage, if TOE –ve use systemic & antibiotic lock therapy for 14 days • Remove CVC if there is clinical deterioration, persisting or relapsing bacteraemia • May retain CVC & use systemic antibiotic for 7 days plus antibiotic lock therapy for 10 – 14 days • Remove CVC if there is clinical deterioration or persisting or relapsing bacteraemia

40. Tunnelled CVC-related blood stream infection Uncomplicated infection Gram-negative bacilli Candida spp. • Remove CVC & treat with antifungal therapy for 14 days after last positive culture • Remove CCV & treat from 10 –14 days • For CVC salvage use systemic & antimicrobial lock therapy for 14 days • If no response, remove CVC & treat with systemic antibiotics for 10 – 14 days

41. Strategies for prevention Quality assurance and continuing education • Standardisation of aseptic care • Staff training in CVC insertion & maintenance • Specialised “IV teams” • Appropriate staffing levels Audit: • site of catheter insertion • choice of catheter material • hand hygiene • aseptic technique • catheter site dressing regimens