Bacterial Etiologies of lower Respiratory Tract Infection among Patients in Intensive Care Unit in National Hospital Riyadh -Saudi Arabia

Abstract

Lower respiratory tract infections (LRTI's) are the most frequent infections among patients in intensive care units. This a cross-sectional study aimed to detect the bacterial etiologies of lower respiratory tract infection among patients in intensive care unit in National Hospital -Riyadh - Saudi Arabia from January to December 2018. A total of 105 intensive care unit patients the specimens were collected ( tracheal aspirate ,bronchial lavage and sputum) and inoculated on MacConkeys agar, blood agar and chocolate agar .Identification and susceptibility test were carried out by use vitek machine .Out of 105 ICU patients 82 (78%) were males and 23 (21.9) females with mean age 52.8 ± 21.6 SD. They were suffering from pneumonia 62(59%), acute bronchitis 4 (3.8%), lung abscess 19 (18%) and cystic fibrosis 14 (13%). From 105 lower respiratory specimens, 99 (94.3%) specimens showed growth and 6 (5.7%) showed no growth. The study demonstrated that high frequency of growth in males and it was 76 (72.4%) and 23 (21.9%) of growth in females patients. High proportion of growth were in tracheal aspirate 93(88%), bronchial lavage 8 (7%), sputum 4 (3%). High frequency of growth was Pseudomonas aeruginosa, 75 (71.4%), Acinetobacter baumannii 69 (65.7%) Klebsiella pneumoniae 62 (59%), Proteus mirabilis 21 (20%), E.coli 12 (11.4%), Providencia 10 (9.5%), Enterobacter aerogenes 7(6.6%), Staphylococcus aureus 21(20%),Serratia marcescens 5(4.7%).Distribution of bacterial isolation according to type of specimens ,in tracheal aspirate specimen showed high proportion of Pseudomonas aeruginosa 67 (72%), in bronchial lavage specimen high frequency of Klebsiella pneumoniae 7 (87.5%) and high frequency of Staphylococcus aureus 3 (75%)in sputum specimen .The distribution of the bacterial isolates according to gender showed frequency of Pseudomonas aeruginosa in females patients 17(73.9%),followed by Klebsiella pneumonia 14(60.8%), Proteus mirabilis 9(39.1%), Acinetobacter baumannici 8(34.7%), Staphylococcus aureus 8(34.7%), E.coli 7(30.4%), Enterobacter aerogenes 4(17.3%), Providencia 4(17.3%), Serratia marcescens 3(13%),whereas Acinetobacter baumannii was predominant in males patients 61(74.3%) followed by Pseudomonas aeruginosa 58(70%), Klebsiella pneumonia 48(58%), Staphylococcus aureus13(15.8%) Proteus mirabilis 12(14.6%), Providencia 6 (7.3%), E.coli 5(6%), Enterobacter aerogenes 3(3.6%). Serratia marcescens 2 (2.4%). The frequency of bacterial isolation according to ages groups showed highly frequency of Klebsiella pneumoniae 8(36%) in age group (20-30) years, in ages groups (31-40) , (41-50) years showed equal proportions in both Klebsiella pneumonia 8 (7.6%), Acinetobacter baumannii 10(9.5%),Pseudomonas aeruginosa 5(4.7%), Proteus mirabilis 7 (6.6%) and Staphylococcus aureus 6(5.7%), E coli 4 (3.8%) ,whereas Acinetobacter baumannii was predominant in age group (51-60) years 46 (43.8%) and Pseudomonas aeruginosa predominant in age group (>61) years 57 (54%). High percentage of Pseudomonas aeruginosa 49 (79%) and Klebsiella pneumonia 18(29%) in pneumonia patients Acinetobacter baumannii 14 (73%) in lung abscess patients, Staphylococus aureus 8 (57%) in cystic fibrosis patients and E.coli 3(75%) in acute bronchitis patients. A single pathogen (klebsiella pneumonia ,Acinetobacter baumannii, Pseudomonas aeruginosa, Proteus mirabilis, Staphylococcus aureus, E.coli,)was isolated from 32(32.32%) patients and 67(66.76%)had mixed bacterial growth, Pseudomonas aeruginosa and Acinetobacter baumannii were more common in co-infection.