5. PATIENTS AND METHODS
5.3. Definitions used in studies
Episode of BSI – isolation of bacteria/fungi from at least one blood culture set (see Table 9) (19) or repeatedly positive cultures with phenotypically similar microorganism within a 7 days period
Nosocomial BSI – bacteremia/fungemia occurring more than 48 h after ad-mission, or resulting from earlier hospitalization within previous 30 days
ICU-acquired BSI – bacteremia/fungemia developing after 48 h of admission to ICU
Primary BSI – bacteremia/fungemia resulting from intravenous or arterial catheter infections and bacteremia/fungemia with unknown origin
CLABSI – primary BSI developing in a patient that had a CL within the 48 hours prior to the infection onset
Secondary BSI – bacteremia/fungemia secondary to infection with the same microorganism at a distant body site or with clinical suspicion without isolation of a microorganism
Polymicrobial BSI – isolation of different species from one or more blood cultures within 48 h
Probable blood culture contaminant – skin commensals (CoNS, Micrococcus sp., Bacillus sp., Propionibacterium sp.,or Corynebacterium sp.) that do not correspond to the BSI definitions for common skin contaminants presented in Table 9
Blood culture set – culture of blood obtained from a single venipuncture and inoculated into one or multiple bottles
Appropriate antimicrobial treatment – the patient received at least one antimicrobial agent that was active against the implicated pathogen in vitro on the day of sampling
Neonate – term and preterm baby (≤ 33 gestational weeks) up to 28 and 90 days of age, respectively
SSI – infection occuring after surgery in the part of the body where the surgery took place (see Table 10) (14)
Surgical wound classification for CS (according to the modified surgical wound classification by Tran et al. (199)
class I (clean) – no rupture of membranes or labor
class II (clean-contaminated) – less than 2 hours of membrane rupture without labor or labor of any length with intact membranes
class III (contaminated) – rupture of membranes greater than 2 hours class IV (dirty) – purulent amniotic fluid
Elective CS – planned procedure and performed when scheduled Emergency CS – all cases not classified under elective CS
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Table 9. The Centers for Disease Control and Prevention definition of laboratory-con-firmed primary BSI used in our study (19).
Laboratory-confirmed bloodstream infection must meet at least one of the following criteria
Criterion 1 Patient has a recognized pathogen cultured from one or more blood cultures
and
organism cultured from blood is not related to an infection at another site.
Criterion 2 Patient has at least one of the following signs or symptoms: fever (>38°C), chills, or hypotension
and
at least one of the following:
a. Common skin contaminant (e.g., diphtheroids, Bacillus sp., Propionibacterium sp., coagulase- negative staphylococci, or micrococci) is cultured from two or more blood cultures drawn on separate occasions
b. Common skin contaminant (e.g., diphtheroids, Bacillus sp.,
Propionibacterium sp., coagulase-negative staphylococci, or micrococci) is cultured from at least one blood culture from a patient with an
intravascular line, and the physician institutes appropriate antimicrobial therapy
and
signs and symptoms and positive laboratory results are not related to an infection at another site
Criterion 3 Patient ≤1 year of age has at least one of the following signs or symptoms: fever (>38°C), hypothermia (<37C°), apnea, or bradycardia and
at least one of the following:
a. Common skin contaminant (e.g., diphtheroids, Bacillus sp.,
Propionibacterium sp., coagulase-negative staphylococci, or micrococci) is cultured from two or more blood cultures drawn on separate occasions b. Common skin contaminant (e.g., diphtheroids, Bacillus sp.,
Propionibacterium sp., coagulase-negative staphylococci, or micrococci) is cultured from at least one blood culture from a patient with an
intravascular line, and physician institutes appropriate antimicrobial therapya
and
signs and symptoms and positive laboratory results are not related to an infection at another site.
a antimicrobial therapy at least 5 days or resolution of symptoms once the device was re-moved
43 Table 10. The CDC definition of SSI (14)
A superficial SSI
Infection occurs within 30 days after the operative procedure and
involves only skin and subcutaneous tissue of the incision and
patient has at least one of the following:
a. Purulent drainage from the superficial incision
b. Organisms isolated from an aseptically obtained culture of fluid or tissue from the superficial incision
c. At least one of the following signs or symptoms of infection: pain or tenderness, localized swelling, redness, or heat, and superficial incision is deliberately opened by surgeon, unless incision is culture-negative
d. Diagnosis of superficial incisional SSI by the surgeon or attending physician Deep incisional SSI
Infection occurs within 30 days after the operative procedure and the infection appears to be related to the operative procedure
and
involves deep soft tissues (e.g., fascial and muscle layers) of the incision and
patient has at least one of the following:
a. Purulent drainage from the deep incision but not from the organ/space component of the surgical site
b. A deep incision spontaneously dehisces or is deliberately opened by a surgeon when the patient has at least one of the following signs or symptoms: fever (>38°C) or localized pain or tenderness, unless incision is culture-negative
c. An abscess or other evidence of infection involving the deep incision is found on direct examination, during reoperation, or by histopathologic or radiologic
examination
d. Diagnosis of a deep incisional SSI by a surgeon or attending physician Organ/space SSI
Infection occurs within 30 days after the operative procedure and the infection appears to be related to the operative procedure
and
infection involves any part of the body, excluding the skin incision, fascia, or muscle layers, that is opened or manipulated during the operative procedure
and
patient has at least one of the following:
a. Purulent drainage from a drain that is placed through a stab wound into the organ/space
b. Organisms isolated from an aseptically obtained culture of fluid or tissue in the organ/space
c. An abscess or other evidence of infection involving the organ/space that is found on direct examination, during reoperation, or by histopathologic or radiologic
examination
d. Diagnosis of an organ/space SSI by a surgeon or attending physician
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