Bacteriology of Body Fluids With an Evaluation of Enrichment Technique to Increase Culture Positivity

Abstract

BACKGROUND: Body fluids like ascitic fluids, pleural fluids, cerebrospinal fluids (CSF) etc. are sent for culture in a clinical microbiology laboratory to achieve etiological diagnosis. However the yield of such cultures is usually very low. So, ongoing monitoring of prevalent pathogenic organisms and their sensitivities help the clinicians institute therapy in absence of a culture report. AIMS: The study was done to identify the common pathogens isolated from body fluids along with their antimicrobial susceptibility pattern and also to evaluate the impact of enrichment on their culture positivity. SETTING AND DESIGN: A 3-month prospective analytical study was done in a tertiary care hospital. MATERIALS AND METHODS: A total of 333 Body fluids were processed; 103 of them were ascitic fluids, 71 pleural fluids, 139 CSF and 20 other fluids. They were processed by plating the direct sample and after enrichment. Enrichment was done by two methods: in SoyabeanCaesin digest broth (274 samples) and by BACTEC (59 samples).Isolates were identified by routine procedures & their antimicrobial susceptibility determined as per CLSI guidelines. The results were analyzed using Microsoft Excel® software using p<0.05 as the cut-off for significance. RESULTS: Gram negative isolate were obtained from 21.3% of the samples. The common isolates were Pseudomonas (20.7%), Acinetobacter (11.6%), Citrobacter (10.7%) and E. coli (10.7%). The antibiotics most effective against Gram negative pathogens were Gentamicin (47.5%), PipercillinTazobactam (51.6%), Amikacin (56.7%) and Cefoperazone-Sulbactam(65.3%). Gram positive isolates, obtained from 9% of the samples, mostly consisted of MSSA, Enterococcus and CONS, for which Ciprofloxacin (48%) followed by Cotrimoxazole (40%) and Erythromycin (28.6%) showed reasonable efficacy. The Culture positivity with direct plating, Soyabean-Caesin broth enrichment and BACTEC was 14.41%, 29.19% and 42.37% respectively. Increase in positivity by Soyabean-Casein broth was maximum for pleural fluids (12%) followed by ascitic fluids (11.6%) and CSF (11.52%).Using automated system the corresponding increases were 20.7%for ascitic fluids and 5.4%for pleural fluids. The mean time for identification using direct plating, enrichment method and BACTEC were 48 hours, 72 hours and 40 hours respectively. CONCLUSION: Gram negative isolates are commonly isolated pathogens from body fluids in our setup. Enrichment of body fluids improved yield of pathogens. In resource-poor settings simple enrichment in blood culture bottles can increase culture positivity of these precious samples.

Aerobic Bacteriological Profile and Antimicrobial Sensitivity Pattern of Bacteria Isolated from Sterile Body Fluids: A Study from a Tertiary Care Hospital in North India

“…In our study, the culture positivity rate was 10.81%. This correlates with the findings of Deb A et al [13] and Kasana et al [3] which showed isolation rate of 14.41% and 14.8% respectively. Other studies like that of Teklehymanot F et al [14] too showed lower culture positive rates of about 14.1%.…”

“…Amongst the Gram negative the most common was Escherichia coli (23.86%) and amongst Gram positive the most common pathogenic organism was Staphylococcus aureus (12.5%). This finding was similar to Deb A et al study [13] and Harshika et al study [18]. However, this is in contrast to the study conducted by Sharma et al [19] where Acinetobacter spp.…”

“…In pleural fluid, Gram negative organisms were isolated more compared to gram positive organisms similar to some studies. [3,13] This is in contrast to few other studies where gram positive organisms accounted for maximum number of cases and Staphylococcus aureus (70%) was the most common pathogen isolated followed by CONS. [22] The isolation of aerobic Gram Negative Bacilli or multiple pathogens from pleural fluid is associated with a poor prognosis and indicates a more aggressive antimicrobial chemotherapy in contrast to the empyema caused by Gram positive pathogens.…”

Bacterial Profile and their Antimicrobial Resistance Patterns from Body Fluids at Tikur Anbesa Specialized Hopital, Addis Ababa, Ethiopia

“…Generally, body fluids like cerebrospinal fluid (CSF), pleural, peritoneal, synovial and pericardial fluids are naturally free of microorganisms under normal circumstance [2]. However, under infectious condition of central nervous system, peritoneum, joints and other sterile sites, different types of bacteria, fungi, virus and parasites could present and change the physicochemical nature of the body fluids [1][2][3].…”

“…bacteria are characterized by having increased WBC count and protein concentration as well as decreased glucose concentration [9]. Bacterial invasion of body fluids cause severe diseases leading to morbidity and mortality unless identified early and treated [1,2]. Though isolation and identification of bacterial etiologies are critical for patient mangment [13] developing resistance against commonly used antibiotics are becoming a challenge for treatment success [14].…”