Survival of ESKAPE pathogen Acinetobacter baumannii in water of different temperatures and pH

Abstract

Bacterium Acinetobacter baumannii is an emergent pathogen associated with nosocomial infections, which can be also found in natural waters. The impact of ecological factors on A. baumannii is insufficiently investigated. The aim was to examine the influence of temperatures (−20 to 80 °C) and pH values (2 to 12) on the survival of environmental and clinical isolates of A. baumannii in nutrient-deprived spring water (SW) and nutrient-rich diluted nutrient broth during 5 months. A. baumannii successfully survived at −20 to 44 °C and neutral pH for 5 months, which is consistent with the persistence of this pathogen in the hospital environment. At temperatures 50 to 80 °C the survival of A. baumannii ranged from 5 days to 5 min. The pH 2 was the most lethal with survival time up to 3 hours, suggesting that acidic conditions are promising for disinfection of water contaminated with A. baumannii. Although the type of media was not statistically significant for long-time survival, the extensively resistant or pandrug-resistant isolates survived better in SW than susceptible or multidrug-resistant isolates. Two distinct colony phenotypes were recorded at extreme temperatures and pH values. The results of this study provide insight into the behaviour of this emerging pathogen in the environment.

Metal-loaded zeolite remediation of soils contaminated with pandrug-resistant Acinetobacter baumannii

“…The bacteria did not multiply, probably due to low soil organic carbon content (0.215 wt%). An earlier study ( 11 ) showed that A. baumannii survived for a long time (150 days) in spring water with a pH of 8.1, which is very close to the pH of our red palaeosol samples (8.43±0.14). As moisture was kept to the maximum water holding capacity, desiccation can be eliminated as the cause of A. baumannii count drop.…”

“…Rises and falls in A. baumannii counts observed from day 68 on could be explained by the “bust and boom” survival strategy, where weak cells die to provide sustenance for the remaining cells ( 9 ). However, the difference between the 32 % survival in red palaeosol in this study and >90 % survival in spring water in our earlier study ( 11 ) suggests that nutrient deprivation is not the only cause of lower A. baumannii survival in red palaeosol. Perhaps it was the presence of Fe in wet red palaeosol that contributed to the drop in A. baumannii count via oxidative stress ( 20 ).…”

“…A. baumannii can survive in a wide moisture, temperature, and pH range ( 9 , 10 , 11 ), which suggests long-term persistence in soil. In a water suspension of strongly acidic palaeosol, A. baumannii survived for one day ( 6 ), while in a pH-neutral technosol it survived for 58 days ( 7 ).…”

Homeoviscous Adaptation of the Acinetobacter baumannii Outer Membrane: Alteration of Lipooligosaccharide Structure during Cold Stress

“…Reduction of the acyl chain length would decrease the Van der Waals molecular interactions between neighboring LPS molecules, resulting in a more fluid membrane ( 2 , 43 ). Although associated primarily with hospital-acquired infections ( 44 ), A. baumannii can be found in a variety of reservoirs ( 45 , 46 ) with environmental isolates capable of surviving in a wide range of temperatures for prolonged periods of time, including in the cold ( 47 ). Thus, the bacterium must be able to maintain membrane fluidity under a variety of conditions.…”

Occurrence of antibiotic‐resistant bacteria on hydroponically grown butterhead lettuce (Lactuca sativa var. capitata)

“…Acinetobacter baumannii has been linked to respiratory infection, pneumonia, and urinary tract infections (Tiwari et al., 2015). The bacteria can be also found in untreated water (Dekic et al., 2018). Antibiotic‐resistant bacteria recovered from lettuce treated with gentamicin included Delftia sp, Cupriavidus pauculus, Sphingobacterium changzhouense, and Ralstonia insidiosa .…”