Background: Lower respiratory tract infections (LRTI) account for a considerable proportion of 
morbidity and antibiotic use. We aimed to identify the causative bacteria, antibiotic sensitivity and 
resistance of hospitalized adult patients due to LRTI in Upper Egypt. Methods: A multicentre 
prospective study was performed at Minia University Hospitals for 3 years. Samples included sputum 
or bronchoalveolar lavage (BAL) for staining and culture, and serum for serology. Samples were 
cultured on 3 bacteriological media (Nutrient, Chocolate, MacConkey's agars). Colonies were 
identified via MicroScan WalkAway-96. Pneumoslide IgM kit was used for detection of atypical 
pathogens via indirect immunofluorescent assay. Results: The predominant isolates in 360 patients 
with CAP were S. pneumoniae (36%), C. pneumoniae (18%), and M. pneumoniae (12%). A higher 
sensitivity was recorded for moxifloxacin, levofloxacin, macrolides, and cefepime. A higher of 
resistance was recorded for doxycycline, cephalosporins, and β-lactam-β-lactamase inhibitors. The 
predominant isolates in 318 patients with HAP were, methicillin-resistant Staphylococcus aureus; 
MRSA (23%), K. pneumoniae (14%), and polymicrobial in 12%. A higher sensitivity was recorded 
for vancomycin, ciprofloxacin, and moxifloxacin. Very high resistance was recorded for β-lactam-βlactamase inhibitors and cephalosporins. The predominant organisms in 376 patients with acute 
exacerbation of chronic obstructive pulmonary diseases (AECOPD) were H. influnzae (30%), S. 
pneumoniae (25%), and M. catarrhalis (18%). A higher sensitivity was recorded for moxifloxacin, 
macrolides and cefepime. A higher rate of resistance was recorded for aminoglycosides and 
cephalosporins. Conclusions: The most predominant bacteria for CAP in Upper Egypt are S. 
pneumoniae and atypical organisms, while that for HAP are MRSA and Gram negative bacteria.