CP-241 Involvement of multidrug resistant flora in invasive infections

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Abstract

Background

The incidence of sepsis and the prevalence of antibiotic resistance of the causative microorganisms are continuously increasing.

Purpose

Determination of bacterial aetiology and antibiotic resistance of microorganisms isolated from blood cultures.

Material and methods

From 133 patients admitted to wards in the Clinical County Emergency Hospital of Craiova for a period of 3 months, 153 blood cultures were collected. They were incubated using Bactec BD and positive results were subjected to microbiological diagnosis using Phoenix BD analyser.

Results

Of the 133 patients tested, 46 (34.59%) had blood cultures positive and 87 (65.41%) negative. With reference to the number of blood cultures, germs were isolated from 47 (30.72%) cultures and the remaining 106 were negative (69.28%). Isolated bacterial species were Enterobacteriaceae (3.92%), Acinetobacter spp (3.27%), Pseudomonas spp (1.96%), Staphylococcus aureus (11.11%), coagulase negative staphylococci (9.15%), Enterococcus spp (65%) and anaerobic bacteria (0.65%). Antibiotic susceptibility testing revealed that Staphylococcus aureus strains, including 73.33% MRSA, were 100% resistant to erythromycin, 85.7% to cefazolin, 63.6% to rifampicin, 61.5% to tetracycline and 57.1% to gentamicin and tetracycline. Coagulase negative staphylococci were resistant to oxacillin (83.3%), erythromycin (75%), cefazolin (66.7%), tetracycline (58.3%) and norfloxacin (55.6%).

Results

All strains of staphylococci were susceptible to vancomycin. Enterobacteriaceae were completely resistant to ampicillin, ceforoxim, cefepime, ceftriaxone, 80% resistant to piperacillin/tazobactam, nitrofuratoin and 60% to ceftazidime and ertapenem. ESBL phenotype was identified in 50% of Enterobacteriaceae isolated and CPE in 34.52%. Pseudomonas aeruginosa was 100% resistant to most antibiotics except colistin and amikacin. Non-fermenters gram negative bacilli were 100% resistant to imipenem and meropenem, 87.5% to ceftazidime, 85.7% to ciprofloxacin, ceftriaxone and cefepime, and 71.4% to gentamicin.

Conclusion

The most common pathogen from blood cultures was Staphylococcus aureus, which had multiple antibiotic resistances, making the management of these invasive infections difficult.

Conclusion

No conflict of interest

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