Usefulness of routine pairing of anaerobic with aerobic blood culture bottles and decision making on antimicrobial therapy


  • Jamal Wadi Al Ramahi Office 11, The Medical Center, Jordan Hospital and medical Center 29 Adeeb Wahbeh Street Amman - Jordan 11118
  • Lamya A. Shanab
  • Abdel Fattah Yacoub
  • Amr Diab
  • Dania Al Momani
  • Fawzi Hleil
  • Haifa Petro
  • Husam Farraj
  • Ghassan Wadi
  • Naheel Halloub
  • Sana Abdulhadi
  • Wala’a Abu Issa



Aerobic blood culture, Anaerobic blood culture, concordant growth



To evaluate the growth concordance in paired aerobic/anaerobic sets, and the impact of the anaerobic growth on patients' antimicrobial management.


This is a prospective multicenter study which was conducted in three hospitals, with total beds of 750 beds and 52 ICU beds. Prospectively, laboratory blood cultures logbooks were daily reviewed and patients from whom blood cultures were ordered were followed, their chart were reviewed. Entries on antimicrobial therapeutic changes were noted for all paired sets. Clinicians were blinded to the study, though they were informed about culture results via the usual work protocol in each hospital.


Collected Blood culture sets totaled 2492; 172 single sets were excluded, and 1160 paired sets were analyzed. 1046 were concordant; 79 sets had bacterial growth and 967 sets had no bacterial growth. 114 sets were discordant; 97 in aerobic bottles, 13 in anaerobic, and 4 in both.

The proportion of agreement for the concordant paired growth sets was 90.2%.  The composite proportion of agreement for sets with any growth (N = 193, composite proportion of agreement = 56%, 95% C.I., 34% - 48%). Cohen kappa composite agreement, measured for the total analyzed paired-sets (N = 1160, K = .52, SE = .038. 95% C.I., .447 - .595). The odds of modifying antimicrobial regimen were for total and subgroups intent to treat odds, based on paired sets showed that one modification took place in one anaerobic growth set (N = 1160, Odds = 0.0008), the odds for all sets with any growth (N = 193, odds = .005), and based on any anaerobic sets (79 concordant, 13 anaerobic, and 4 discordant) with bacterial growth (N = 96: odds = 0.010).


The study demonstrates that the proportion of agreement among paired sets were high, and needless to include anaerobic sets in routine blood culture collection. Also the decision-making of anti-infective treatment on patients based on anaerobic blood culture growth was not evident.

Author Biography

Jamal Wadi Al Ramahi, Office 11, The Medical Center, Jordan Hospital and medical Center 29 Adeeb Wahbeh Street Amman - Jordan 11118

Chairman, The Infection Prevention and Control Committee

Al Khalidi Medical Center


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