ISSN: 0973-7510
E-ISSN: 2581-690X
, Sai Vineela Pilli1, Muthusamy Raman2 and Padmaja Yarlagadda3Bloodstream infections caused by bacteria can cause potentially fatal sepsis, which needs immediate antibiotic therapy to prevent morbidity and death of patient. Blood culture remains the gold standard procedure that provides the vital information for the diagnosis and guiding appropriate antimicrobial treatment. The study sought to assess the antibiotic susceptibility and bacteriological profile of blood culture isolates in intensive care unit (ICU) settings. Understanding the incidence of diverse bacteria in ICU blood cultures, as well as their antibiotic susceptibility, is crucial for developing effective treatment plans that work. During the study period, 3,594 blood cultures underwent analysis, revealing 388 cases positive for growth. To identify isolates, VITEK 2 GN ID cards were utilized, capable of discerning both fermentative and non-fermentative bacteria. Further, VITEK 2 GP ID was employed for selected Gram-positive cocci. Antibiotic susceptibility testing was conducted using VITEK 2 AST 407 Critical Care cards for fermentative and non-fermentative Gram-negative bacilli, with subsequent testing on VITEK 2 AST 628 cards for Gram-positive cocci. Out of which, 230 (59.2%) were Enterobacteriaceae isolates, 87 (22.4%) were non-fermenters, and 71 (18.2%) were Gram-positive cocci. The majority of the blood culture isolates were multidrug-resistant (MDR), extended-spectrum beta-lactamase (ESBL) producers, carbapenemase producers, and methicillin-resistant Staphylococcus aureus (MRSA). In our study, we observed carbapenem-resistant Klebsiella spp., Escherichia coli (E. coli), Acinetobacter baumannii, Pseudomonas aeruginosa, and Burkholderia cepacia, which is alarming. The results show the diverse range of microorganisms responsible for bloodstream infections in severely ill ICU patients. Understanding the antibiotic susceptibility characteristics of these isolates is crucial for developing effective therapeutic regimens.
Bloodstream Infections, Enterobacteriaceae, Intensive Care Unit (ICU), Multidrug-resistant (MDR), Non-fermenters, Methicillin-resistant Staphylococcus aureus (MRSA), Extended-spectrum Beta-lactamase (ESBL)
The term bacteremia is a blood-borne bacterial infection and colonization frequently isn’t a serious threat to life. Without any apparent clinical symptoms, there are several physiological causes for the transitory bacteremia.1 However, bacterial infection of blood results in potentially fatal sepsis. Bloodstream infections (BSIs) are a significant contributor to increased mortality and morbidity on a global level.2 Chills, fever, tachycardia, malaise, hyperventilation, toxicity, hypertension and prostration, are typical indications in septicemia. Acute renal failure with an adverse outcome and the occurrence of disseminated intravascular coagulation are serious consequences. Blood culture provides crucial information about several diseases, such as endocarditis, pyrexia of unclear origin, and pneumonia, in a patient who is suspected of having sepsis.3
The most frequent reasons for hospital admissions are bacterial infections that lead to nosocomial infections, particularly in intensive care unit (ICU) settings.4 Severity of the patient’s condition, the amount of time they spend with invasive devices and procedures, the duration of time they interact with medical staff and other variables are all linked to an increased risk of infection and the duration of the hospital stay.5 Risk factors for bloodstream infections are complex and varied. Age can be a significant factor, especially for elderly patients and newborns. Premorbid medical disorders such as diabetes mellitus, malignancies, renal failure, burns, and prior hospitalization also play an important role. The use of peripheral and central venous catheters on patients is a critical factor.6 Bloodstream infections are potentially fatal, so it’s important to quickly identify the causing organism and assess its resistance to antibiotics. Bacteremia and septicemia are caused by bacteria, both gram-positive and gram-negative. Endotoxic shock, another name for gram-negative septicemia, is a more serious condition than gram-positive septicemia.7
If the illness is brought on by resistant bacteria morbidity and death will rise, resulting in significant financial loss that includes the use of more costly drugs to treat infections and the potential for antibiotic resistance. MDR organism-caused illnesses have a higher propensity to lengthen hospital stays, raise mortality rates, and require more costly antibiotics for treatment.8 Numerous bacteria, including gram-negative ones such as Escherichia coli, Klebsiella spp., Serratia spp., Pseudomonas spp., Salmonella spp. and Enterobacter spp., alongside gram-positive ones like Staphylococcus spp., Streptococcus spp. and Enterococcus spp. have been connect to the development of blood flow contaminations.9,10 A recent investigation, however, indicates that the number of bloodstream infections (BSIs) caused by multidrug-resistant bacteria has increased. These bacteria include members of the Enterobacteriaceae family, as well as some Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci. Other Gram-negative bacteria include Klebsiella spp., Pseudomonas spp., Acinetobacter spp. and Citrobacter spp. The majority of these bacteria produce extended-spectrum beta-lactamases (ESBL).11,12 Increasing antibiotic resistance in bacteria from hospital infections and community-acquired illnesses has lowered the effectiveness of many antimicrobial drugs.13,14
While numerous studies and infection control principles exist, this study also provides a combined organism-wise antibiogram, which includes less commonly described non-fermenters like Burkholderia cepacia, Aeromonas salmonicida, Stenotrophomonas maltophilia, and rare isolates as well, such as Pandoraea spp. and Rhizobacter rhizobium. The integration of detailed susceptibility patterns rendered the observed patterns more clinically useful and, in addition to guiding local empirical therapy, facilitated ICU-specific antimicrobial stewardship. A relevant bacteriological profile of ICU blood cultures, with a clear distinction between fermentative and non-fermentative Gram-negative bacteria, is presented. Many studies have described the causative agents of bloodstream infections in ICUs, the microbiologic profile and antibiotic resistance patterns tend to considerably differ in different areas and periods of time, given the presence of emerging resistance mechanisms and infection control practices at the local level. This study is unique in presenting a recent and regionally specific profile.
We conducted a twelve-month prospective exploratory study at Saveetha Medical College in Thandalam, Chennai, from January 2023 to December 2023. A total of 3594 samples were collected from all Intensive Care Unit (ICU) settings like Medical Intensive Care Unit (MICU), Surgical Intensive Care Unit (SICU), Pediatric Intensive Care Unit (PICU), and Neonatal Intensive Care Unit (NICU) following stringent aseptic methods, which included thoroughly disinfecting the venous site utilizing the Triple Swab technique with 70% alcohol, povidone iodine, and alcohol.
Inclusion criteria
Patients brought to the intensive care unit with laboratory evidence of bloodstream infection, as indicated by positive blood cultures, along with clinical signs of infection such as fever and hypotension, are eligible for inclusion. Additionally, patients with risk factors such as recent surgery, use of a central venous catheter, or prolonged stay in the ICU may also be included. Antimicrobial susceptibility testing is a prerequisite for inclusion to ensure that the study evaluates the effectiveness of antibiotics against isolated microorganisms.
Exclusion criteria
Patients with known viral infections, those with compromised immune systems, those on antibiotic medication before enrollment, and patients whose medical records were insufficient are a few examples of these. Patients who are unable to provide informed permission or who have polymicrobial bloodstream infections may also be excluded.
If it was feasible, the samples were collected from two distinct locations that were twenty minutes apart. There were 2 samples taken in total. Blood was drawn, with an average of 8 to 10 ml per site. Commercial aerobic blood culture vials from BD BACTEC (Becton Dickinson automated blood culture system) were then filled with the obtained blood samples. that contain soybean casein digest broth, yeast, amino acids, sugar, vitamins and sodium polyanethol sulphonate as a blood thinner. In pediatric cases, a blood sample of 1-2 ml was drawn and administered.15 Upon collection, these bottles were set up promptly in a fully automated blood culture system, the BD Bactec FX-40, to identify growth in the blood culture. Beep alarms with color coding after positive detection. The blood from the vial was subcultured on both MacConkey and blood agar before being incubated at 37 °C overnight in accordance with standard protocols.16 Following an evaluation of the colony features and the growth’s Gram stain, species identification was performed using Biomerieux’s Advanced Expert Phenotypic System that is completely automated (VITEK 2) and to detect patterns of antimicrobial susceptibility.17
To identify isolates, VITEK 2 GN ID cards were utilized, capable of discerning both fermentative and non-fermentative bacteria. Further, VITEK 2 GP ID was employed for selected Gram-positive cocci. Antibiotic susceptibility testing was conducted using VITEK 2 AST 407 critical care cards for fermentative and non-fermentative Gram-negative bacilli, with subsequent testing on VITEK 2 AST 628 cards for Gram-positive cocci. Isolates were identified as extended-spectrum beta-lactamases (ESBL) with CRE, MRSA, and AmpC-producing organisms.
Antibiotic susceptibility was assessed in accordance with Clinical and Laboratory Standards Institute (CLSI) recommendations. For analysis and presentation, intermediate results were grouped with resistant isolates (CLSI M100, 2024 edition).
Statistical analysis and data management
SPSS version 20.0 and Microsoft Excel 2007 were used for data entry, results interpretation and analysis. Descriptive statistics were used for analyzing the patient demographic profile, the pattern of prescribing antibiotics and the isolation of different organisms and their antibiograms. Results were expressed as frequencies and percentages. No inferential statistical tests were used.
Of the 3594 blood cultures examined during the research period, 388 (10.7%) were positive for growth. In the ICU settings, SICU had the highest number of cases at 183 (47.1%), while PICU had 11 cases (2.8%). In terms of gender distribution, males comprised the majority (70.8%) across all the units compared to females as shown in Table 1.
Table (1):
Gender-wise distribution of bloodstream infection (BSI) cases in various ICU settings
Type of ICU |
Total cases n (%) |
Males n (%) |
Females n (%) |
|---|---|---|---|
SICU |
183 (47.16%) |
128 (46.54%) |
55 (48.67%) |
MICU |
181 (46.64%) |
131 (47.63%) |
50 (44.24%) |
NICU |
13 (3.35%) |
8 (2.90%) |
5 (4.42%) |
PICU |
11 (2.83%) |
8 (2.90%) |
3 (2.65%) |
Total |
388 |
275 (70.87%) |
113 (29.1%) |
Table 1 shows the number and percentage of BSI cases among male and female patients in the Surgical Intensive Care Unit (SICU), Medical Intensive Care Unit (MICU), Neonatal Intensive Care Unit (NICU), and Pediatric Intensive Care Unit (PICU).
Out of 388 positive cultures, 230 (59.2%) were Enterobacteriaceae isolates, 87 (22.4%) were non-fermenters and 71 (18.2%) were Gram-positive cocci.
Among 230 Enterobacteriaceae isolates, the predominant isolate was Klebsiella spp. accounting for 101 (43.9%) cases, while the lowest case was one instance of Proteus mirabilis (0.4%), as highlighted in Table 2.
Table (2):
Prevalence of Enterobacteriaceae isolates in BSI among ICU patients
Enterobacteriaceae isolates |
ICU-n (%) |
|---|---|
Klebsiella spp. |
101 (43.91%) |
Escherichia coli |
92 (40%) |
Salmonella typhi |
11 (4.78%) |
Enterobacter aerogens |
9 (3.91%) |
Serratia marcescens |
7 (3.04%) |
Citrobacter freundii |
4 (1.73%) |
Pantoea dispersia |
3 (1.30%) |
Salmonella parathphi A |
2 (0.86%) |
Proteus mirabilis |
1 (0.43%) |
Total |
230 (100%) |
Among the 87 (22.4%) non-fermenter isolates, the predominant isolate was A. baumannii with 32 cases (36.7%), while the lowest were one (1.1%) each of Elizabethkingia meningoseptica, Rhizobacter rhizobium, and Pandoraea spp. respectively, as highlighted in Table 3.
Table (3):
Prevalence of non-fermenters in BSI among ICU patients
Non Fermentative Gram-negative bacteria |
ICU-n (%) |
|---|---|
Acinetobacter baumanii |
32 (36.78%) |
Pseudomonas aeroginosa |
17 (19.54%) |
Burkholderia cepacia |
16 (18.39%) |
Aeromonas salmonicida |
14 (16.09%) |
Stenotrophomonas maltophilia |
4 (4.59%) |
Sphingomonas paucimobilis |
1 (1.14%) |
Elizabethkingia meningoseptica |
1 (1.14%) |
Rhizobacter rhizobium |
1 (1.14%) |
Pandoraea spp. |
1 (1.14%) |
Total |
87 (100%) |
Among the 71 (18.2%) Gram-positive isolates, the most common type was coagulase-negative staphylococci (CoNS), accounting for 36 (50.7%) cases, while the least common was Streptococcus agalactiae with one case (1.4%), as shown in Table 4.
Table (4):
Prevalence of Gram-positive cocci in BSI among ICU patients
Gram-positive cocci |
ICU-n (%) |
|---|---|
Coagulase negative Staphylococci |
36 (50.70%) |
Staphylococcus aureus |
25 (35.21%) |
Enterococcus faecalis |
9 (12.67%) |
Streptococcus agalactiae |
1 (1.40%) |
Total |
71 (100%) |
Investigation evaluated the susceptibility of Enterobacterial isolates’ to antibiotics as highlighted in Table 5 and 6.
Table (5):
Antibiotic susceptibility Patterns of Enterobacterial Isolates in BSI
Antibiotic |
K. pneumoniae 101 (25.96%) |
E. coli 92 (23.65%) |
Citrobacter spp. 4 (1.02%) |
Pantoea dispersia 3 (0.77%) |
Enterobacter spp. 9 (2.31%) |
|---|---|---|---|---|---|
Amikacin |
5 (4.95%) |
0 |
0 |
0 |
3 (33.33%) |
Cefepime |
23 (22.77%) |
40 (43.47%) |
3 (75%) |
1 (33.33%) |
2 (22.22%) |
Cefoperazone/ Sulbactum |
1 (0.99%) |
4 (4.34%) |
1 (25%) |
0 |
0 |
Ceftazidime |
22 (21.78%) |
0 |
0 |
0 |
1 (11.11%) |
Ciprofloxacin |
0 |
20 (21.73%) |
2 (50%) |
0 |
3 (33.33%) |
Colistin |
65 (64.35%) |
70 (76.08%) |
0 |
1 (33.33%) |
5 (55.55%) |
Gentamicin |
0 |
0 |
0 |
0 |
1 (11.11%) |
Imipenem |
4 (3.96%) |
18 (19.56%) |
0 |
0 |
0 |
Meropenem |
31 (30.69%) |
52 (56.52%) |
3 (75%) |
0 |
4 (44.44%) |
Piperacillin/ Tazobactum |
0 |
0 |
0 |
0 |
1 (11.11%) |
Tetracycline |
28 (27.72%) |
43 (46.73%) |
2 (50%) |
2 (66.67%) |
6 (66.66%) |
Tigecycline |
0 |
0 |
3 (75%) |
0 |
0 |
Ceftrixone |
0 |
35 (38.04%) |
0 |
0 |
0 |
Amox/clav |
12 (11.88%) |
1 (1.08%) |
0 |
0 |
1 (11.11%) |
Cotrimoxazole |
0 |
23 (25%) |
2 (50%) |
1 (33.33%) |
4 (44.44%) |
ceftizoxime |
22 (21.78%) |
35 (38.04%) |
1 (25%) |
0 |
2 (22.22%) |
Tobramycin |
26 (25.74%) |
51 (55.43%) |
3 (75%) |
1 (33.33%) |
5 (55.55%) |
Minocycline |
0 |
0 |
0 |
1 (33.33%) |
0 |
Ceftazidime/ Avibactum |
37 (36.63%) |
47 (51.09%) |
3 (75%) |
0 |
4 (44.44%) |
Chloramphenicol |
30 (29.70%) |
59 (64.13%) |
0 |
0 |
2 (22.22%) |
Polymyxin B |
65 (64.35%) |
66 (71.74%) |
0 |
0 |
1 (11.11%) |
Ceftazidime+ Tazobactum |
33 (32.67%) |
44 (47.83%) |
0 |
0 |
1 (11.11%) |
Note. Susceptibility testing followed CLSI guidelines, with isolates showing intermediate susceptibility considered resistant in this analysis.
Table (6):
Antibiotic susceptibility Patterns of Enterobacterial Isolates in BSI
Antibiotic |
P. mirabilis 1 (0.25%) |
S. marcesence 7 (1.79%) |
S. typhi 11 (2.82%) |
S. paratyphi A 2 (0.51%) |
|---|---|---|---|---|
Amikacin |
0 |
0 |
||
Ceftazidime |
0 |
0 |
6 (54.54%) |
2 (100%) |
Cefoperazone/ Sulbactum |
0 |
0 |
NT |
NT |
Netilmicin |
1 (100%) |
6 (85.71%) |
NT |
NT |
Ciprofloxacin |
0 |
0 |
5 (45.45%) |
1 (50%) |
Tobramycin |
0 |
4 (57.14%) |
4 (36.36%) |
0 |
Gentamicin |
0 |
3 (42.85%) |
2 (18.18%) |
2 (100%) |
Imipenem |
0 |
0 |
9 (81.81%) |
1 (50%) |
Meropenem |
0 |
6 (85.71%) |
7 (63.63%) |
1 (50%) |
Piperacillin/ Tazobactum |
0 |
0 |
4 (36.36%) |
1 (50%) |
Tigecycline |
0 |
4 (57.14%) |
NT |
NT |
colistin |
0 |
0 |
NT |
NT |
Azithromycin |
NT |
NT |
NT |
0 |
Ceftrixone |
NT |
NT |
4 (36.36%) |
1 (50%) |
Cotrimoxazole |
NT |
NT |
5 (45.45%) |
2 (100%) |
Minocycline |
NT |
NT |
4 (36.36%) |
1 (50%) |
Chloramphenicol |
NT |
NT |
8 (72.72%) |
1 (50%) |
Note. Susceptibility testing followed CLSI guidelines, with isolates showing intermediate susceptibility considered resistant in this analysis.
Among Enterobacteriaceae E. coli and Klebsiella spp. showed highest susceptibility rates Colistin, Polymyxin B, Ceftazidime/Avibactam, Meropenem as shown in Table 5. The susceptibility rates to other antibiotics varied. These results highlight the importance of individualized antibiotic treatment for the management of bloodstream infections, especially in critical care units. A number of antibiotics, including Amikacin, Cefepime, Cefoperazone/Sulbactam, Ceftazidime, Imipenem, Piperacillin/Tazobactam, Ceftazidime/Avibactam, Polymyxin B, and Ceftazidime/Tazobactam, did not show susceptibility against these non-fermenter isolates in the study.
Table (7):
Exploring Antibiotic susceptibility Patterns: non-fermenter Isolates in BSI
Antibiotic |
A. baumanii 32 (8.22%) |
P. aeruginosa 17 (4.37%) |
B. cepacia 16 (4.11%) |
S. maltophilia 4 (1.02%) |
S. paucimobilis 1 (0.25%) |
|---|---|---|---|---|---|
Amikacin |
0 |
2 (11.76%) |
0 |
0 |
0 |
Cefepime |
5 (15.62%) |
4 (23.53%) |
3 (18.75%) |
0 |
1 (100%) |
Cefoperazone/ Sulbactum |
0 |
3 (17.65%) |
1 (6.25%) |
0 |
0 |
Levofloxacin |
8 (25%) |
9 (52.94%) |
7 (43.75%) |
4 (100%) |
1 (100%) |
Ceftazidime |
0 |
5 (29.41%) |
2 (12.5%) |
0 |
0 |
Ciprofloxacin |
4 (12.5%) |
2 (11.76%) |
0 |
0 |
1 (100%) |
Colistin |
12 (37.5%) |
0 |
0 |
0 |
1 (100%) |
Imipenem |
0 |
0 |
0 |
0 |
0 |
Meropenem |
9 (28.12%) |
10 (58.82%) |
10 (62.5%) |
0 |
1 (100%) |
Netilmicin |
12 (37.5%) |
7 (41.18%) |
5 (31.25%) |
0 |
0 |
Piperacillin/ Tazobactum |
0 |
0 |
0 |
0 |
0 |
Tetracycline |
12 (37.5%) |
4 (23.53%) |
5 (31.25%) |
0 |
0 |
Tigecycline |
0 |
0 |
0 |
0 |
0 |
Ceftrixone |
12 (37.5%) |
1 (5.88%) |
8 (50%) |
0 |
1 (100%) |
Azetreonam |
0 |
0 |
0 |
0 |
0 |
Tobramycin |
11 (34.37%) |
11 (64.71%) |
3 (18.75%) |
0 |
1 (100%) |
Minocycline |
5 (15.62%) |
0 |
8 (50%) |
1 (25%) |
0 |
Ceftazidime/ Avibactum |
0 |
5 (29.41%) |
4 (25%) |
0 |
0 |
Polymyxin B |
13 (40.62%) |
3 (17.65%) |
0 |
0 |
0 |
Ceftazidime + Tazobactum |
0 |
4 (23.53%) |
1 (6.25%) |
0 |
NT |
Note. Susceptibility testing followed CLSI guidelines, with isolates showing intermediate susceptibility considered resistant in this analysis.
Table 7 shows the antibiotic susceptibility patterns of non-fermentative Gram-negative bacteria that were found in the blood of ICU patients with bloodstream infections (BSIs). The information shows how many and what proportion of isolates of Acinetobacter baumannii, Pseudomonas aeruginosa, Burkholderia cepacia, Stenotrophomonas maltophilia, and Sphingomonas paucimobilis are responsive to different antibiotics. NT: Not Tested.
Table (8):
Exploring Antibiotic susceptibility Patterns of non-fermentative Gram-negative isolates in BSI
Antibiotic |
A. salmonicida 14 (3.59%) |
E. meningoseptica 1 (0.25%) |
R. rhizobium 1 (0.25%) |
Pandorea spp. 1 (0.25%) |
|---|---|---|---|---|
Amikacin |
0 |
0 |
0 |
1 (100%) |
Cefepime |
0 |
0 |
0 |
0 |
Cefoperazone/ Sulbactum |
1 (7.14%) |
0 |
0 |
0 |
Levofloxacin |
2 (14.28%) |
0 |
1 (100%) |
1 (100%) |
Ceftazidime |
1 (7.14%) |
0 |
0 |
0 |
Ciprofloxacin |
1 (7.14%) |
0 |
1 (100%) |
1 (100%) |
Colistin |
1 (7.14%) |
0 |
0 |
0 |
Imipenem |
0 |
0 |
0 |
0 |
Meropenem |
2 (14.28%) |
0 |
0 |
0 |
Netilmicin |
1 (7.14%) |
0 |
0 |
0 |
Piperacillin/ Tazobactum |
0 |
0 |
0 |
0 |
Tetracycline |
1 (7.14%) |
1 (100%) |
0 |
0 |
Tigecycline |
1 (7.14%) |
0 |
0 |
0 |
Ceftrixone |
0 |
0 |
0 |
0 |
Azetronam |
1 (7.14%) |
NT |
NT |
NT |
Tobramycin |
0 |
0 |
0 |
1 (100%) |
Minocycline |
1 (7.14%) |
0 |
0 |
0 |
Ceftazidime/ |
0 |
0 |
0 |
0 |
Avibactum |
||||
Polymyxin B |
0 |
0 |
0 |
0 |
Ceftazidime + Tazobactum |
0 |
0 |
0 |
0 |
Note. Susceptibility testing followed CLSI guidelines, with isolates showing intermediate susceptibility considered resistant in this analysis.
Table 8 shows the antibiotic susceptibility profiles of Aeromonas salmonicida, Elizabethkingia meningoseptica, Rhizobium radiobacter, and Pandoraea spp. isolated from ICU patients with BSIs. The data show the number and percentage of isolates sensitive to various antibiotics. NT: Not Tested.
Table (9):
Exploring Antibiotic susceptibility Patterns: gram-positive Isolates in BSI
Antibiotic |
S. aureus 25 (6.42%) |
CoNS 36 (9.25%) |
E. faecalis 9 (2.31%) |
S. agalactiae 1 (0.25%) |
|---|---|---|---|---|
Benzylpenicilin |
9 (36%) |
2 (5.55%) |
5 (56%) |
0 |
cefoxitin |
8 (32%) |
11 (30.55%) |
NT |
0 |
Erythromycin |
10 (40%) |
8 (22.22%) |
2 (22%) |
0 |
Clindamycin |
20 (80%) |
8 (22.22%) |
0 |
0 |
Cotrimoxazole |
7 (28%) |
19 (52.77%) |
0 |
0 |
Gentamicin |
17 (68%) |
13 (36.11%) |
0 |
0 |
Ciprofloxacin |
6 (24%) |
9 (25%) |
2 (22%) |
0 |
Vancomycin |
23 (92%) |
18 (50%) |
0 |
1 (100%) |
Teicoplanin |
24 (96%) |
17 (47.22%) |
8 (89%) |
0 |
Linezolid |
23 (92%) |
20 (55.55%) |
9 (100%) |
1 (100%) |
Rifampicin |
21 (84%) |
18 (50%) |
0 |
0 |
High level Gentamicin |
NT |
NT |
6 (67%) |
0 |
Amoxicilin/clavulinic acid |
0 |
3 (8.33%) |
0 |
0 |
Tetracycline |
19 (76%) |
16 (44.44%) |
1 (11%) |
1 (100%) |
Ampicilin |
NT |
NT |
0 |
NT |
Daptomycin |
23 (92%) |
16 (44.44%) |
8 (89%) |
0 |
Amikacin |
0 |
5 (13.88%) |
0 |
0 |
Cefoperazone/ Sulbactum |
0 |
0 |
0 |
0 |
Note. Susceptibility testing followed CLSI guidelines, with isolates showing intermediate susceptibility considered resistant in this analysis.
Table 9 shows sensitivity gram-positive organism patterns. Staphylococcus aureus showed highest sensitive to teicoplanin followed by followed by vancomycin, linezolid, daptomycin, rifampicin, clindamycin, and tetracycline (76%). Resistance was higher against erythromycin, benzylpenicillin, co-trimoxazole, and ciprofloxacin. Enterococcus faecalis shows 100% sensitivity to linezolid with least sensitivity to erythromycin, ciprofloxacin and tetracycline Streptococcus agalactiae demonstrated 100% sensitivity to tetracycline, vancomycin, and linezolid.
The study set out to identify the bacterial profile and susceptibility pattern of the organisms that cause bloodstream infections (BSIs). The prevalence of blood culture positivity was observed in 10.7% of samples in our study. The low culture positivity rate of 10.7% seen in this investigation is comparable to results from a few other studies carried out by Khanal et al. and Gohel et al., which showed culture positivity rates from BSI patients in India of 10.3% and 9.2%, respectively.12,18 Culshaw et al. reported 12.2%, which is slightly higher than our study findings.19 Similar to studies by Kalpesh et al. and Oluwalana et al., CoNS (50.7%) and S. aureus (35.2%) were the most common isolates among Gram-positive isolates in our study.12,20 Among isolates, E. coli, Klebsiella spp. and A. baumannii complex were the common Gram-negative isolates in this study. This is comparable to the studies conducted by Gohel, Bhatia et al., ASM Areef et al., and Fatima et al.12,21-23 Gram-negative isolates caused more septicemia in this study than Gram-positive isolates, as has been shown in other studies as well.24-26
Enterobacteriaceae group was responsible for the majority of sepsis cases (59.2%). Among all Enterobacteriaceae isolates, Klebsiella spp., E. coli, followed by Salmonella typhi and Enterobacter spp. were predominant. This study has similarities to those carried out by Palewar et al., Gupta et al., Vanitha et al and Banik et al.24-27
Among non-fermenter isolates, A. baumannii (36.78%) predominated, followed by P. aeruginosa (19.5%) and B. cepacia (18.3%). This is comparable to the studies conducted by ASM Ahsan et al., Fasih et al., and Baral et al.22,23,28
Among 71 (18.2%) isolates of Gram-positive cocci, S. aureus and Enterococcus spp. showed >80% sensitivity to Teicoplanin, Vancomycin, Linezolid, Daptomycin, and Clindamycin. A total of 42 methicillin-resistant strains including CoNS and S. aureus were not 100% sensitive to Vancomycin. This is in contrast to the study conducted by Oluwalana et al.2 but consistent with studies conducted by Garg et al., Gupta et al., and Kavitha et al.7,25,29 Teicoplanin should be considered as a treatment option for MRSA strains before Vancomycin, as most of the MRSA and VRSA strains were sensitive to Teicoplanin in this study. Therefore, Teicoplanin should be taken into consideration to treat Vancomycin-resistant Staphylococcus strains (VRSA). This is consistent with studies conducted by Garg et al. and Kalowsky et al.7,30
Among Enterobacteriaceae isolates, there was poor sensitivity to quinolones, penicillins, cephalosporins, carbapenems, aminoglycosides, and colistin. This is similar to the studies conducted by Kalpesh et al., Ahsan et al., and Prakash et al.12,22,31 The susceptibility and resistance patterns found are consistent with CLSI-defined breakpoints (CLSI M100, 2024), as described in the Methods.32
Among non-fermenter isolates, A. baumannii was predominantly 100% resistant to carbapenems, aminoglycosides, cephalosporins, and monobactam drugs, followed by P. aeruginosa, B. cepacia, S. maltophilia, and S. paucimobilis. This is consistent with the studies conducted by Ahsan et al. and Baral et al.22,28
In conclusion, implementation of hospital-wide program like bloodstream infection (BSI) surveillance in ICU settings improves patient outcomes and lowers the burden of infections. Essentially, using antibiograms in conjunction with BSI surveillance accounts to a multimodal strategy for antibiotic administration and infection control in critical care units. Hospitals may upgrade patient safety, mitigate the risk of bloodstream infections, along with support the overall goals of antimicrobial stewardship and healthcare quality improvement by effectively using these innovations.
ACKNOWLEDGMENTS
The authors express their gratitude to all healthcare workers and laboratory personnel who assisted in the collection and analysis of blood culture samples in the ICU. Their effort and skills were critical to the success of our investigation. The authors would also like to thank the Institutional Ethics Committee for their assistance and permission to conduct this study.
CONFLICT OF INTEREST
The authors declare that there is no conflict of interest.
AUTHORS’ CONTRIBUTION
All authors listed have made a substantial, direct and intellectual contribution to the work, and approved it for publication.
FUNDING
None.
DATA AVAILABILITY
The datasets generated and/or analysed during the current study are available from the corresponding author on reasonable request.
ETHICS STATEMENT
The study protocol was reviewed and approved by the Institutional Ethics Committee, Saveetha Medical College, with approval no.: SMC/IEC/2024/078
INFORMED CONSENT
Written informed consent was obtained from the participants before enrolling in the study.
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