Spectrum of pathogenic bacteria isolated from the bronchoalveolar lavage in a tertiary care centre at Hyderabad

Introduction

Pneumonia is one of the major factors which is known to contribute to high death rates seen all over the world.¹ Through the appropriate usage of antibiotics the pneumonia can be cured, but in several instances due to lack of prompt diagnosis, inappropriate use of antibiotics, and lack of adequate therapy could lead to the death of patients. Early diagnosis and identification of the pathogenic bacteria and initiation of the antibiotic therapy helps and it is crucial for the successful management of the patient.3, 2 The type of specimen is very important in diagnosis of the pneumonia. Bronchoalevolar lavage (BAL) is one of the important specimen for definite identification of bacterial pathogen contributing for the genesis of pneumonia.5, 4 There are several advantages and studies have proved that BAL is one of the important specimen contributing in proper diagnosis through identifying the microbial pathogen in more than 80% of cases. The spectrum of bacteria isolated from the BAL vary in different geographical regions as well as the bacterial resistance pattern. In present study we aim to identify the spectrum of pathogenic bacteria isolated from the BAL and their antibiotic sensitivity pattern.

Materials and Methods

The retrospective study and the data analysis has been carried for in the department of Microbiology, Kamineni Academy of Medical Sciences and Research Centre for a period of one year from January 2015-2016 for the total number of BAL sent for culture and their culture report and antibiotic sensitivity pattern. The study carried out in patients with symptoms of pneumonia, BAL samples were collected through application of bronchoscopy. All the samples were cultured on blood agar, MacConkey Agar media and Chromogenic agar media, and culture plates were incubated at 37°C overnight, the identification of culture was carried out using biochemical reactions and sensitivity to various antibiotics was assessed using the Kirby - Bauer disk diffusion method.

Results

A total 90 cases of BAL specimens were received in one year for the bacterial culture from the 55 males and 45 females with the mean age of 50.5 (Min-19 yrs to Max-72 yrs). A total of 28 cases (31%) cases were culture positive in which the Pseudomonas aeruginosa has grown in 15 cases (52%), Klebsiella pneumoniae has grown in 7 cases (28%), Escherichia.coli grown in 3 cases (10%) and Streptococcus pneumoniae in 3 cases 10%).

The organisms isolated have shown variable drug resistance pattern including resistant to ciprofloxacin in 80% of isolates, Azetronam in 40% of cases, cefipime in 40% of cases, and, found sensitive to gentamicin in 80% of cases, carbapenem in 80% of cases, cefazolin in 60% of cases. The Sterptococcus pneumoniae found sensitive to penicillin, gentamicin, erythromycin and vancomycin.

Figure 1

Streptococcus pneumoniae aeruginosa

Figure 2

Pseudomonas aeruginosa

Figure 3

Escherichia coli

Figure 4

Klebsiella pneumoniae

Discussion

Pneumonia is the inflammatory condition of the lung and main etiological factors for genesis of pneumonia are bacteria. Evaluation of the type of the organisms isolated and their antibiotic sensitivity pattern helps the clinicians to treat the patient in time and reduces the burden of morbidity and mortality. In the present study 31% of cases were culture positive similar to the study carried Bhat et al6 which has shown the isolation of bacteria from BAL was about 35% of cases, but the contrast to our study as study conducted by Rahul et al has found the isolation of organisms more than 90% of pneumonia cases.7 The most common organism isolated in our study was Pseudomonas aeruginosa, similar to the Bhat et al followed by Klebisella and Escherichia.coli species. In the present study we find the gram negative bacteria are highly sensitive to carbapenem drugs when compared to other studies, which has shown rise in carbapenem resistance in isolates from BAL.9, 8 A study conducted by Rahul et al found high prevalence of bacterial drug resistance in bacteria isolated from BAL.7

Conclusion

We have evaluated the BAL culture isolates at our tertiary centre and found the most common isolate was Pseudomonas aeruginosa which are sensitive to most of the common antibiotics used. The culture of BAL is useful for intervention and treatment to reduce the morbidity and mortality of the patient.

Source of Funding

None.

Conflict of Interest

None.