Objectives:

The purpose of this study was to determine aerobic and anaerobic bacteria colonising pleural drains in patients with non-small cell lung cancer (NSCLC) undergoing thoracic surgery and to define antimicrobial agents susceptibility of isolated strains. Routine antimicrobial prophylaxis included piperacillin or cefuroxime. In some cases beta-lactam was used in combination with amikacin.

Methods:

Material for research was fluid from pleural drains collected from 34 patients aged 38–72 years two times – on the day of pulmonary resection and on the fourth day after operation. Samples were routinely cultured under aerobic and anaerobic conditions and determined using Api system (bioMerieux). Antimicrobial resistance was estimated by the disc diffusion method according NCCLS recommendations.

Results:

Aerobic (49 strains) and anaerobic (23 strains) bacteria were found in 30 (44%) and 15 (22%) samples, respectively. Among aerobic bacteria, Gram-negative rods (22 strains; 18 – belonging to non-fermenting rods) and coagulase negative staphylococci (CNS; 14 strains) were most often cultured. Fifteen strains of non-fermenting rods and 11 isolates of CNS were classified as multidrug resistant (MDR) organisms. Two isolates of S. marcescens were producers of extended spectrum beta-lactamases (ESBLs) and inducible beta-lactamases (IBLs). All staphylococci were susceptible to vancomycin and teicoplanin. CNS strains resistant to penicillin and oxacillin but sensitive to amoxicillin/clavulanate were most frequently isolated. Only two methicillin-resistant strains, belonging to S. haemolyticus were found. The most common anaerobic bacteria were from genera Eubacterium (nine strains) and Actinomyces (six strains). All of them were highly susceptible to antimicrobial agents except metronidazol (69.6% resistant strains) and chloramphenicol (52.2% resistant isolates).

Conclusion:

Colonisation of pleural drains does not mean infection, however knowledge about bacterial species found in drain fluid in a local population and antimicrobial resistance (especially MDR strains) has a major impact on the success of prophylaxis and therapy of potential postoperative infections.