Community acquired pneumonia among adult patients at an Egyptian university hospital: bacterial etiology, susceptibility profile and evaluation of the response to initial empiric antibiotic therapy.

Background: Effective empirical antibiotic therapy for community acquired pneumonia (CAP), based on frequently updated data about the pattern of bacterial distribution and their antimicrobial susceptibilities, is mandatory.

Aim: To identify the bacterial etiology of CAP in adults and their antibiotic susceptibility patterns and to evaluate the response to initial empirical antibiotic therapy in an Egyptian university hospital.

Settings And Design: A cross-sectional hospital-based study.

Patients And Methods: CAP cases were selected by systemic random sampling from those admitted to the chest department. All were evaluated at admission and 4 days after starting empiric therapy. Typical bacteria were isolated, identified and tested for their antibiotic susceptibility. An indirect IF assay was used to diagnose atypical bacteria. Clinical response to initial empiric antibiotic therapy was clinically, laboratory and radiologically evaluated.

Results: Two hundred and seventy CAP patients were included. Bacteria represented 50.4% of them. was the most prevalent bacterium (10.37%) followed by and (7.78% each). Overall, 76.2% of isolates showed a multidrug resistant phenotype: 82.61% (19/23) , 89.66 % (26/29) , 65.22% (15/23) , 87.50% (7/8) and 81.25 % (13/16) . Broad spectrum β-lactams, especially carbapenems, and moxifloxacin showed in vitro efficacy on most of the tested isolates. Forty-three cases (15.9%) were nonresponders, 37 (86%) of them showed bacterial etiology. The highest rate of nonresponsiveness (30.43%) was observed in cases receiving antipseudomonal/antipneumococcal β-lactam plus a fluoroquinolone for suspected infection.

Conclusion: Multidrug resistance in bacteria causing CAP and high frequency of isolation of hospital pathogens are prominent features of this study. Azithromycin containing regimens were associated with the lowest rates of nonresponsiveness. Development and implementation of an antibiotic stewardship program are highly recommended for CAP management.