Body fluids play a substantial role in transporting nutrients, regulating body temperature, and aiding respiration (Abdinia et al.). Normally sterile fluids such as cerebrospinal, pleural, peritoneal, synovial, and pericardial fluid can become infected by microorganisms—bacteria, fungi, viruses, or parasites—leading to severe morbidity and mortality (Deb et al.; Hasbun et al.). Early detection and identification of pathogens are essential for proper management and reduced hospital stay (Sujatha et al.). Common pathogens include Escherichia coli, Klebsiella spp., Haemophilus influenzae, Staphylococcus aureus, Neisseria meningitidis, Pseudomonas spp., and Acinetobacter spp. Because these infections are medical emergencies, regular monitoring of local antibiograms is essential for effective empirical therapy and public-health antibiotic policies.

MATERIALS AND METHODS

Study Design and Duration: This cross-sectional study was conducted in the Department of Microbiology, Government Mohan Kumaramangalam Medical College Hospital (GMKMCH), Salem, Tamilnadu from June 2020 to April 2021. Sample Collection: A total of 465 sterile body fluid samples including cerebrospinal, pleural, peritoneal, synovial, and pericardial fluids were collected using strict aseptic precautions and transported within two hours. Culture and Identification: Samples were inoculated on Blood agar, MacConkey agar, and Chocolate agar plates and incubated at 37°C for 24–48 hours. Bacterial identification was performed using Gram staining, colony morphology, and standard biochemical reactions such as oxidase, indole, citrate, urease and triple sugar iron test. Antimicrobial Susceptibility: Antibiotic sensitivity testing was carried out using the Kirby–Bauer disk diffusion technique on Mueller–Hinton agar as per CLSI 2020 guidelines.

Quality Control: Reference ATCC strains—E. coli 25922, Staphylococcus aureus 25923, and Pseudomonas aeruginosa 27853 were employed as ATCC.

Data Analysis: Data were analyzed using Microsoft Excel 2021 and presented as percentages.

Ethics: Institutional Ethical Committee approval was obtained prior to commencement of the study. Ethical clearance was obtained from the Institutional Ethics Committee.

Inclusion criteria included all body-fluid samples received from admitted patients with suspected infection, irrespective of age or sex. Exclusion criteria excluded blood samples, patients with recent antibiotic therapy (within two weeks), contaminated samples, and samples delayed beyond two hours after collection.

Each specimen was examined microscopically (Gram stain) and cultured on blood agar, MacConkey agar, and chocolate agar. Bacterial identification was performed by stan biochemical tests (Collee et al.). Susceptibility testing was performed using the Kirby–Bauer disk-diffusion method on Mueller-Hinton agar and interpreted as per CLSI 2020 guidelines.

Out of 465 processed samples, 99 (21.3%) exhibited bacterial growth. Gram-negative organisms predominated, particularly Pseudomonas aeruginosa, Klebsiella species, Acinetobacter species, and Escherichia coli. Gram-positive isolates included Staphylococcus aureus and coagulase-negative Staphylococci (CONS). Lactose-fermenting isolates demonstrated excellent sensitivity to β-lactam/β-lactamase inhibitor combinations and carbapenems, whereas non-fermenting isolates exhibited varying resistance patterns.

Table 1 & Figure 1: Growth pattern of body fluids

Table 2 & Figure 2: Bacterialogical profile of different body fluid samples

Table 3: Antibiotic susceptibility pattern of Gram negative bacteria (GNB). (N = 33)

Table 4: Antibiotic susceptibility pattern of Non Fermenting Gram negative bacteria (NFGNB). (N = 41)

Table 5 & Figure 5: Antibiotic susceptibility pattern of Gram-positive isolates (n – 25)

DISCUSSION

The overall culture positivity rate of 21.3 % was consistent with studies by Sharma et al., Harshika et al., and Vishalakshi et al., who reported positivity between 20–30 %. Pseudomonas aeruginosa was the predominant isolate, aligning with findings of Harshika et al. and Sharma et al. Klebsiella spp. and Acinetobacter spp. were next most frequent, similar to reports by Vishalakshi et al. and Abdinia et al. S. aureus and CONS isolation patterns correlated with Sujatha et al. and Deb et al. All Gram-positive isolates remained 100 % sensitive to vancomycin and linezolid. Carbapenems and piperacillin-tazobactam retained the highest activity among Gram-negative isolates. These trends emphasize the need for ongoing surveillance to guide empirical antimicrobial therapy.

CONCLUSION

Gram-negative bacteria remain the predominant pathogen among sterile body-fluid isolates, with Pseudomonas aeruginosa being the most common organism. Carbapenems and β-lactam/β-lactamase inhibitor combinations remain effective empirical treatment options while resistance to cephalosporins and fluroquinolones is rising. Continuous surveillance of local bacteriological profiles and antimicrobial patterns is essential for rational antibiotic therapy and stewardship

Ethical Clearance

Obtained from Institutional Ethics Committee, GMKMCH, Salem.

Acknowledgement

The authors thank the Department of Microbiology, GMKMCH, Salem, for technical support.

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