European Journal of Cardiovascular Medicine

Neonatal sepsis is a significant cause of morbidity and mortality in newborns, accounting for 30-50% of neonatal deaths worldwide. It is a life-threatening condition characterized by a systemic inflammatory response to infection, primarily caused by bacterial pathogens1,2. Early diagnosis and timely administration of appropriate antibiotics are crucial for improving survival outcomes3.

The incidence of neonatal sepsis varies depending on geographical region, healthcare facilities, and infection control measures4. In developing countries, poor hygiene practices, preterm birth, and prolonged hospital stays contribute to higher infection rates5. Neonates admitted to Neonatal Intensive Care Units (NICUs) are particularly vulnerable due to their immature immune systems and increased exposure to invasive procedures6,7.

Despite advancements in neonatal care, diagnosing and managing neonatal infections remain a challenge due to non-specific clinical symptoms and increasing antimicrobial resistance. The pattern of bacterial isolates and their antibiotic susceptibility vary across different healthcare settings, requiring continuous monitoring to optimize empirical antibiotic therapy8.

This study aims to assess the bacteriological profile and antimicrobial sensitivity patterns of blood culture isolates in neonates with sepsis admitted to the NICU at GGH, Guntur. Understanding the prevalence of causative organisms and their resistance patterns will help formulate effective infection control strategies and antibiotic policies, ultimately reducing neonatal morbidity and mortality.

AimS & Objectives of the Study

1. To determine the bacteriological profile of blood culture isolates in neonates with sepsis.
2. To evaluate the antimicrobial susceptibility patterns of the isolated pathogens.
3. To identify maternal and neonatal risk factors associated with neonatal sepsis.
4. To assess neonatal outcomes based on blood culture findings.

Study Design and Setting

This was a prospective observational study conducted in the Neonatal Intensive Care Unit (NICU) of Government General Hospital (GGH), Guntur. The study aimed to assess the bacteriological profile and antimicrobial sensitivity patterns of blood culture isolates in neonates with sepsis.

Study Duration

The study was conducted from November 2022 to  June 2024.

Sample Size

A total of 150 neonates diagnosed with sepsis were included in the study.

Inclusion Criteria

Neonates admitted to NICU with clinical signs and symptoms suggestive of sepsis, along with one or more of the following maternal and neonatal risk factors:

Maternal Risk Factors:

Premature rupture of membranes (PROM) for >18 hours

More than three per vaginal examinations during labor

Chorioamnionitis

Foul smelling liquor

Maternal fever (>38°C) during labor

Neonatal Risk Factors:

Prematurity (<37 weeks gestation)

Perinatal asphyxia

Meconium aspiration syndrome (MAS)

Exclusion Criteria

Neonates with life-threatening congenital anomalies such as:

Congenital diaphragmatic hernia

Tracheoesophageal fistula

Meningoencephalocele

Anencephaly

Case Definition of Neonatal Sepsis

Neonatal sepsis was diagnosed based on clinical symptoms and positive blood culture findings. The clinical criteria included:

Hypothermia or fever

Lethargy, poor feeding

Respiratory distress, apnea

Shock, metabolic acidosis

Seizures

Sepsis was categorized into early-onset sepsis (EOS) (occurring within 72 hours of birth) and late-onset sepsis (LOS) (occurring after 72 hours).

Data Collection

Clinical and demographic data were collected using a structured case sheet proforma. The following data points were recorded: Gestational age, birth weight, gender, place of birth (inborn/outborn) Maternal and neonatal risk factors, Clinical symptoms and laboratory findings, Blood culture results and antibiotic sensitivity patterns, Neonatal outcomes (survival or mortality)

Laboratory Methods.

Blood Culture:

A minimum of 1 mL of blood was collected under aseptic conditions and inoculated into BacT/ALERT blood culture bottles. Cultures were incubated for 48-72 hours, and bacterial isolates were identified using standard microbiological techniques.

C-Reactive Protein (CRP) Testing: CRP levels were assessed as a marker of infection, with values >6 mg/L considered positive.

Antimicrobial Sensitivity Testing: Antibiotic susceptibility of isolated bacteria was determined using the Kirby-Bauer disk diffusion method, following Clinical and Laboratory Standards Institute (CLSI) guidelines. The following antibiotics were tested: Ampicillin, Gentamicin, Amikacin, Piperacillin-Tazobactam, Cefotaxime, Ceftazidime, Meropenem, Vancomycin

Statistical Analysis

Data entry was performed using Microsoft Excel 2013, and statistical analysis was conducted using SPSS Version 16. Descriptive statistics (frequencies, percentages, means, standard deviations) were used to summarize the findings. Chi-square test was used for categorical variables, and Unpaired t-test was used for parametric data. A p-value <0.05 was considered statistically significant.

Ethical Considerations

Institutional Ethical Committee (IEC) approval was obtained before the commencement of the study.Informed consent was obtained from the neonates’ parents or guardians before inclusion in the study.All data confidentiality and patient anonymity were maintained throughout the research.

Demographic and Clinical Characteristics

A total of 150 neonates diagnosed with sepsis were included in the study. The distribution of cases based on gestational age, birth weight, gender, and place of birth is presented in Table 1.

Table 1: Distribution of Neonatal Characteristics

Sepsis Classification and Risk Factors

The cases were classified into early-onset sepsis (EOS) and late-onset sepsis (LOS). Maternal and neonatal risk factors were also analyzed and summarized in Figure 1& 2.

Figure No:1. Distribution of Sepsis Type

Figure No:2. Distribution of Neonatal & Maternal Risk Factors

Clinical Presentation and Laboratory Findings

The most common clinical manifestations observed in neonates with sepsis included refusal of feeds (68%), lethargy (66%), and respiratory distress (51.3%). Invasive ventilation was required in 65.3% of cases. CRP (C-reactive protein) was positive in 89.3% of neonates, indicating high inflammatory response.

Table 3: Clinical Presentation and Laboratory Findings

Figure No:3.Clinical Presentation

Bacteriological Profile and Outcomes

Blood culture positivity was found in 150 cases, with Klebsiella species (60.7%) being the most common isolate, followed by Staphylococcus aureus (22%), Pseudomonas (9.3%), and Acinetobacter (8%).

The overall survival rate was 78.6%, while 21.3% of neonates succumbed to the infection. The correlation between bacterial isolates and neonatal outcomes is detailed in Table 4.

Table 4: Blood Culture Findings and Neonatal Outcomes

Figure No:4. Blood Culture Findings

Antibiotic Sensitivity Patterns

The antibiotic resistance patterns of the bacterial isolates were analyzed. Klebsiella showed high resistance to ampicillin and cefotaxime, while being sensitive to piperacillin/tazobactam and meropenem. Staphylococcus aureus demonstrated 100% sensitivity to vancomycin. The antibiotic sensitivity data is summarized in Table 5.

Table 5: Antibiotic Sensitivity Patterns

Neonatal sepsis remains a leading cause of morbidity and mortality among neonates, especially in middle and lower-income countries. Blood culture remains the gold standard for the diagnosis of neonatal septicemia.

Gestational Age and Birth Weight

The study found that 38.7% of neonates were born between 32-36 weeks, while 23.3% were born before 32 weeks. This highlights a significant prevalence of preterm births, which aligns with the study by Opare-Asamoah K et al11. (2023), reporting a similar mean gestational age of 35.6 weeks. Preterm neonates are at a higher risk of developing sepsis due to an immature immune system and increased exposure to invasive procedures9,10.

Birth weight distribution showed that 61.3% of neonates weighed 1.5-2.5 kg, which is consistent with the findings of Patel D et al12 (2014), who also observed a high prevalence of low birth weight (LBW) neonates in septic cases. The association between prematurity, low birth weight, and sepsis suggests the need for improved perinatal care to reduce neonatal infections.

Sepsis Type and Risk Factors

This study classified 40% of cases as early-onset sepsis (EOS) and 60% as late-onset sepsis (LOS), similar to findings from Reddy KA et al15 (87.5%  were of LOS), whereas Patel D et al12, who reported a higher incidence of EOS .Our findings indicate that LOS was more prevalent, possibly due to prolonged hospital stays, NICU exposure, and use of invasive medical devices.

Maternal risk factors such as prolonged rupture of membranes (PROM >18 hours) (34%), multiple per vaginal examinations (>3) (32.6%), and chorioamnionitis (22.7%) were strongly associated with neonatal sepsis. These results are supported by Almohammady MN et al13. (2019), who also identified PROM and maternal infections as significant risk factors. Reducing unnecessary per vaginal examinations and improving infection control measures during labor can help reduce neonatal sepsis rates.

Clinical Presentation and Laboratory Findings

The most common clinical symptoms observed in septic neonates were: Refusal of feeds (68%),  Lethargy (66%), Respiratory distress (51.3%), Shock (40.7%)

These findings are consistent with Obadare  et al14. (2023), who identified  respiratory distress,fever , refusal of feeds,and lethargy as key indicators of neonatal sepsis. The presence of shock in 40.7% of cases suggests a severe systemic response, requiring early recognition and aggressive management. Laboratory analysis showed CRP positivity in 89.3% of cases, reinforcing its role as a sensitive marker for neonatal sepsis. However, CRP alone is not specific, emphasizing the need for blood cultures to confirm infection.

Bacteriological Profile and Outcomes

Klebsiella pneumoniae (60.7%) was the most frequently isolated organism, followed by Staphylococcus aureus (22%), Pseudomonas (9.3%), and Acinetobacter (8%). This is consistent with studies by Almohammady MN et al13. (2019), Reddy KA et al15 and Patel D et al. , which reported Klebsiella as the predominant pathogen. The high prevalence of Gram-negative organisms suggests the need for targeted antibiotic policies to combat resistance.

The overall mortality rate was 21.3%, with Klebsiella infections contributing to 61.4% of deaths, similar to the findings by Obadare  et al14. (2023). The high fatality rate associated with Klebsiella emphasizes the need for stringent infection control measures in NICUs.

Antibiotic Sensitivity Patterns

Klebsiella showed high resistance to ampicillin and cefotaxime, consistent with findings by Patel D et al12 and Obadare et al14. (2023). Piperacillin/tazobactam and meropenem remained effective, making them the preferred choices for Gram-negative infections. Vancomycin was 100% effective against Staphylococcus aureus, confirming its continued efficacy for Gram-positive infections.

Comparison with Previous Studies

The current study identified Klebsiella pneumoniae (60.7%) as the most common pathogen in neonatal sepsis, with a mortality rate of 21.3% and high resistance to ampicillin and cefotaxime. Similar findings were reported by Reddy KA et al15, Patel et al12.  where Klebsiella (42.4%) was predominant, showing resistance to ampicillin, gentamicin, and cephalosporins. However, Obadare et al14. (2023) found Staphylococcus aureus (51.2%) to be the leading cause of neonatal sepsis, emphasizing increasing resistance to commonly used antibiotics. These variations suggest regional differences in bacterial profiles and antibiotic resistance patterns, highlighting the need for continuous surveillance and tailored empirical treatment protocols to combat neonatal sepsis effectively. The rising resistance to first-line antibiotics highlights the urgent need for implementation antibiotic stewardship activities  in NICUs.

Clinical Implications and Future Recommendations

Early screening and diagnosis using blood cultures and CRP testing are essential for timely treatment. NICU infection control measures, such as hand hygiene and judicious antibiotic use, can help prevent nosocomial infections. Regular antibiotic sensitivity surveillance should guide empirical therapy to reduce emergence of resistance. Effective maternal healthcare interventions are needed to prevent & reduce sepsis risk factors such as PROM and maternal infections.

This study confirms that Klebsiella pneumoniae is the leading cause of neonatal sepsis, with high resistance to commonly used antibiotics (ampicillin and cefotaxime), while being sensitive to piperacillin/tazobactam and meropenem. +Strengthening infection control measures, implementing antibiotic stewardship programs, and improving maternal health can significantly reduce neonatal sepsis burden and improve survival outcomes.

Acknowledgements

I sincerely express my gratitude to Dr. B. Deva Kumar, Professor & HOD, Department of Pediatrics, Guntur Medical College, Guntur, for his invaluable guidance, constant encouragement, and support throughout the study. His expertise and ideology have been instrumental in shaping this research. I also extend my appreciation to my colleagues and the NICU staff for their cooperation and assistance in data collection.

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