Some authors report that the abnormal carrier state is not only a marker of illness but is a disease on its own (19,20), as overgrowth of AGNB in the gut has been shown to cause immuno-paralysis.
Severe infections with multi-resistant AGNB and MRSA can be the reason for the admission to the ICU.
Abnormal carriage was defined as the isolation of AGNB including Klebsiella, Enterobacter, Citrobacter, Morganella, Proteus, Acinetobacter, Serratia, Pseudomonas species and MRSA in throat and/or rectum in any concentration.
The combination of polymyxin and tobramycin covers all AGNB including Proteus, Morganella and Serratia species being the gap in the spectrum of the polymyxins.
Ceftazidime (100 mg/kg/day via intravenous continuous infusion for four days (33)) was given to patients classified as belonging to the hospital group because they were considered to be exposed to abnormal AGNB such as P.
One hundred and forty (22%) patients had surveillance cultures positive for AGNB in their admission flora (Table 1).
Finally, the mean carriage indices of AGNB were 3.6 ([+ or -]0.87 SD) in the community group and 3.5 ([+ or -]0.88 SD) in the hospital group.
Seventy-two patients (16 community, 56 hospital) carried AGNB resistant to third generation cephalosporins and 67 patients carried MRSA intrinsically resistant to third generation cephalosporins.
Diagnostic samples identified 49 (7.9%) patients with bacteria resistant to third generation cephalosporins (MRSA n=22, resistant AGNB n=27).
Antibiotics were administered on the wards before admission to the ICU in 196 (60%) patients (Table 1) and 82 (41.8%) carried ceftazidime resistant AGNB. The most common antimicrobials employed were beta-lactams (63%), followed by quinolones (11%), glycopeptides (8%) and metronidazole (8%).
* Thirty percent of the study population carried abnormal flora on arrival to ICU; 22 and 11% carried AGNB and MRSA, respectively.
* Bacteria resistant to third generation cephalosporins used as the parenteral component of SDD, including MRSA and AGNB, were present in surveillance cultures to a higher extent (threefold) than in the diagnostic samples.