Volume 1, Issue 1

 

Guidelines for the management of Adults with Health Care-Associated Pneumonia

December 31, 1969

ABSTRACT

Healthcare-associated pneumonia (HCAP) is a unique entity that differs from community-acquired pneumonia in both bacteriology and outcomes and has similarities to hospital-acquired pneumonia and ventilator-associated pneumonia. HCAP patients are at higher risk of potential multidrug-resistant pathogens, including MRSA and multidrug resistant gram-negative organisms, especially Pseudomonas aeruginosa and Acinetobacter spp., but also extended-spectrum β-lactamases (ESBLs) and carbipenamases. This manuscript reviews the epidemiology, etiology, antibiotic treatment, prevention and clinical outcomes of hospitalized HCAP patients. We will focus our attention on the potential multidrug-resistant pathogens to suggest a new treatment strategy for these patients.

Introduction:

HCAP was defined as a distinct clinical entity in the most recent American Thoracic Society/Infectious Diseases Society of America nosocomial pneumonia guidelines2 in order to identify a subset of patients at risk for harboring multidrug-resistant organisms despite their residence in the community. Consensus-derived criteria for HCAP included the following: pneumonia occurring in patients with prior hospitalization in an acute care facility for ≥ 2 days within 90 days before the onset of HCAP; residence in a nursing home or long-term–care facility; recent receipt of IV antibiotic therapy, chemotherapy, or wound care, within 30 days before infection with HCAP; or attending a hospital or dialysis clinic.2 An important distinction of HCAP, attributed to the above-described risk factors, is that the offending pathogens are often multidrug-resistant bacteria.2 Therefore, the initial treatment of HCAP should be similar to that for hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), which also differentiates HCAP from CAP.3 This is particularly important for clinicians working in emergency departments and ICUs to recognize so that appropriate initial antimicrobial therapy is not delayed. Several studies46 have demonstrated that delaying the delivery of pathogen-appropriate antimicrobial therapy to patients with CAP and VAP results in excess mortality.

Epidemiology and Pathogens:

The presence of HCAP, and other health-care–associated infections, has been most thoroughly described in the United States.7,8 Kollef et al3 evaluated the prevalence of HCAP after reviewing a large database of 4,543 patients with culture-positive pneumonia and identified 20% as having HCAP. Skilled Nursing home accounted for nearly half of all patients with HCAP (49.6%)( ref 3)

 The percentage of patients with a culture positive for S aureus was similar among those with HCAP and those with HAP (46.7% and 47.1%, respectively), Micek et al9 also validated HCAP as a distinct entity from CAP by evaluating patients with microbiologically confirmed pneumonia who had been admitted to Barnes-Jewish Hospital in St. Louis, MO. Among 639 patients with microbiologically confirmed pneumonia, 431 (67.4%) were classified as having HCAP. HCAP patients had a significantly greater risk of receiving inappropriate antimicrobial therapy (28.3% vs 13.0%, respectively; p < 0.001).MRSA and P aeruginosa were the most common pathogens associated with HCAP, while S pneumoniae and Haemophilus species were most frequent in CAP. El Solh et al(10) described 88 patients with microbiologically confirmed Nursing Home Associated Pneumonia (NHAP), in whom the previous use of antibiotics, poor functional status and underlying chronic comorbidities were found to be predictive of the presence of multidrug-resistant bacteria. Carratalà et al11  reported that compared to the patients with CAP, patients with HCAP were significantly older, had greater comorbidity and were more commonly classified into high-risk pneumonia severity index classes.

 

TABLE 1. RISK FACTORS FOR MULTIDRUG-RESISTANT

PATHOGENS IN HEALTHCARE-ASSOCIATED PNEUMONIA.

  • Antimicrobial therapy in preceding 90 d
  • Current hospitalization of 5 d or more
  • High frequency of antibiotic resistance in the community or in the specific hospital unit
  • Presence of risk factors for HCAP:
    • Hospitalization for 2 d or more in the preceding 90 d
    • Residence in a nursing home or extended care facility
    • Home infusion therapy (including antibiotics)
    • Chronic dialysis within 30 d
    • Home wound care
    • Family member with multidrug-resistant pathogen
  • Immunosuppressive disease and/or therapy

Diagnosis and Treatment:

HCAP should be considered in all patients presenting with pneumonia from the community and Healthcare associated facilities (skilled Nursing facility and Dialysis centers) and patients should be carefully screened for risk factors for multidrug resistant pathogens as in  table 1. Blood and sputum cultures should be obtained on all patients suspected of HCAP regardless of severity of disease.

Key recommendations and principles of evidence- based guidelines is as follows:

Initial appropriate empiric antibiotics selection should be guided by patient specific risk factors, underlying medical conditions, gram stain of lower airways secretion, institution specific prevalence of potential organisms and current antibiogram. Recent exposure to a class of antibiotics can predict subsequent resistance to a variety of agents, usually to the same class but occasionally to other classes of agents as well (236).

Refer to Table 2 and 3, for potential pathogens with corresponding initial appropriate antibiotic choice and dose..  Pneumonia severity index scores (13) should  help guide admissions to appropriate clinical settings i.e. medical ward vs ICU. Deescalation therapy should be based on culture and sensitivity studies. Algorithm in table 4 presents a summary of treatment protocol.

Outcome:

 HCAP had a significantly greater hospital mortality rate (24.6% vs 9.1%, respectively; p < 0.001) compared to patients with CAP.(9). Kolef et al(3) reported  mean mortality rates (19.8% and 18.8%, respectively) were similar for these two groups of patients as well, with both statistically greater than the mortality rate for CAP (10.0%).Initial  Inappropriate empiric therapy tripled the risk of hospital death (1). Delayed escalation of therapy based on sensitivity study did not mitigate the high mortality.

Early, appropriate, broad spectrum  antibiotics in adequate doses is recommended. Antibiotics combination is preferred over monotherapy for potential multidrug- resistant gram negative organisms to prevent emergence of resistance.( refer to tables 2 and 3)

A short duration of antibiotics ( 7 to 8 days) is recommended for patients with uncomplicated HCAP who have received initially appropriate therapy and with no evidence of infection for non-fermenting gram negative bacilli.

Table 2: Initial Empiric Therapy combination for HCAP

  • Potential Pathogens Combination Antibiotic Therapy*
  • Pathogens listed in Table 3 and Antipseudomonal cephalosporin
  • MDR pathogens (cefepime, ceftazidime)
  • Pseudomonas aeruginosa or
  • Klebsiella pneumoniae (ESBL_)† Antipseudomonal carbepenem
  • Acinetobacter species † (imipenem or meropenem) or B_-Lactam/B_-lactamase inhibitor
  • (piperacillin–tazobactam) plus Antipseudomonal fluoroquinolone†
  • (ciprofloxacin or levofloxacin) or Aminoglycoside
  • (amikacin, gentamicin, or tobramycin) Plus Methicillin-resistant Staphylococcus Linezolid or vancomycin‡ aureus (MRSA)

Table 3: Initial Antibiotics and Dosage.

AntibioticDosage*
Antipseudomonal cephalosporin
Cefepime 1–2 g every 8–12 h
Ceftazidime 2 g every 8 h
Carbepenems
Imipenem 500 mg every 6 h or 1 g every 8 h
Meropenem 1 g every 8 h
_-Lactam/_-lactamase inhibitor
Piperacillin–tazobactam 4.5 g every 6 h
Aminoglycosides
Gentamicin 7 mg/kg per d†
Tobramycin 7 mg/kg per d†
Amikacin 20 mg/kg per d†
Antipseudomonal quinolones
Levofloxacin 750 mg every d
Ciprofloxacin 400 mg every 8 h
Vancomycin 15 mg/kg every 12 h‡
Linezolid 600 mg every 12h

Table 4: Summary of management Strategy.

Prevention:

Strict infection control measures, maximal barrier protection, hand washing between patient contacts, de-escalation of antibiotics therapy, short duration of antibiotics will help minimize the occurrence of HCAP and prevent emergence of multi-drug resistance. (12)

Summary: In patients presenting from community  with pneumonia, HCAP should be differentiated from CAP based on well defined criteria and risk factors for multidrug resistant organisms. HCAP has similar morbidity and mortality compared to Hospital acquired pneumonia and higher than CAP. Prompt and appropriate Initial broad spectrum antibiotics targeted against the potential multidrug resistant organism results in improved outcome. De-escalation therapy based on pathogen specific therapy and 7 day duration of therapy will help prevent emergence of resistant strains.

References:

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