The Association between Acinetobacter baumannii Bacteremia and Blood PH Imbalance in Critically ICU Patients

Abstract

Background: Acinetobacter baumannii is one of the most significant nosocomial infections, particularly in intensive care units, and has high illness and death rates. Abnormal blood pH (i.e., acidosis) is also a key indicator of disease severity and outcome in cases resulting from blood contamination. Aim: This study was conducted to investigate the association between blood pH disorders due to A. baumannii infection and antibiotic treatment with clinical outcomes in patients in the RICU. Material and Method: A Prospective observational study conducted in the respiratory critical care Unit, Najaf Teaching Hospital, from July 2024 to July 2025 on 44 cases that confirmed having had Acinetobacter baumannii. Blood samples were obtained for bacterial isolation, performed using conventional microbiological techniques in addition to the VITEK apparatus. Antimicrobial sensitivity testing was carried out according to the CLSI/EUCAST guidelines. Blood acid-base status was determined by arterial blood gas analysis. The demographic details, the antibiotic used, and the pH status were documented. All statistical analyses were performed using SPSS version 31, and a p-value <0.05 was considered statistically significant. Results: The mean age of the patients was 53.6 ± 18.2 years, and there was a male predominance (63.6%). The most frequently prescribed antibiotics were colistin (52.3%) , followed by meropenem (15.9%) and ceftriaxone (11.4%). Multi-antibiotic resistance was also found to occur at a rate of 20.5%. Worse mortality rates were observed in patients with acidosis (72.2%), particularly when colistin was administered in cases with acidosis who died (81.8%). The results showed that patients treated with ceftriaxone or meropenem had higher survival rates, and age was also shown to be an important risk factor, with the highest mortality rate recorded among the age group (≥70 years). In contrast, no significant differences in mortality rates were observed between the sexes. Conclusion: The results indicate that blood acidity disorders, especially acidosis, significantly affect death rates in ICU patients with A. baumannii, and the risk increases in cases of multiple resistance or when using colistin. Monitoring blood pH, examining antibiotic sensitivity, and implementing early intervention for treating acidosis disorders are important tools for improving clinical outcomes and reducing mortality rates in this category of patients.