Nosocomial infection: main cause in development of septic complications during postoperative period

Objective

To study the frequency of emergence of nosocomial infection in ICU.

Design

Retrospective study of data from case records and flow sheets. One thousand four hundred and fifty-one postoperative patients admitted to ICU during 1999-2000.

Measurements and main results

Of 1451 patients in our ICU during 2 years, we include those 613 (42.2%) who stayed for more than 72 hours. According to results from cultures we divided them to three groups. Group 1 included 355 (57.9%) patients without bacterial growth. Group 2 included patients with proved nosocomial infections (NCI). We obtained samples: 898 from urinary catheters (376 positive - 41.9%), 552 from tracheal tube (457 positive - 82.8%), 597 from blood (282 positive - 47.2%), 64 intradermal segments from central venous lines (34 positive - 53.1%), and 17 from sputum (15 positive - 88.2%). The most common place for development of NCI in our ICU is respiratory tract. On 5th ICU day the tract became infected in almost 56% of the patients. The major role among pathogens played Acinetobacter spp. (27.4%), Citrobacter spp. (20.3%), P. aeruginosa (12% and Serratia spp. (10%). The second place for NCI development is reserved for blood-stream infections. Almost the half of the cultures (47.2%) showed bacterial growth. The isolated pathogens were the same: Acinetobacter spp. (19%), Serratia spp. (16%), but there was substantial rise in emergence of S. epidermidis during the last year. Its frequency almost equalized that of Acinetobacter spp. The other two main sources for NCI were urine and CV catheters. They remained on 3rd and 4th places. Group 3 included patients with endogenous surgical infections. In this group we obtained samples from surgical wounds and drainages. In 1999 25.6% of cultures showed bacterial growth. During next 2000 this figure rose nearly twice (48.3%). The leading role played the same Acinetobacter spp., Citrobacter spp., P. aeruginosa, Enterococcus spp. and E. coli. The role of S. epidermidis increased greatly during this period.

Conclusions

There was a rise in frequency of nosocomial and secondary endogenous surgical infection in 1999-2000. The frequency of Gram-positive pathogens, namely S. epidermidis, nearly equalized that of Gram-negative flora as a cause of nosocomial infection. Nosocomial infection remained the main cause of septic complications in postoperative ICU patients.