UV-resistant Acinetobacter sp. isolates from Andean wetlands display high catalase activity

Capua, Cecilia Beatriz Di; Bortolotti, Ana; Farı́as, Marı́a Eugenia; Cortez, Néstor

doi:10.1111/j.1574-6968.2011.02231.x

Cited by 42 publications

(47 citation statements)

References 40 publications

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“…Other studies investigating differences in UV survivorship have focused on bacteria isolated from one particular type of environment, such as high-altitude lakes or other extreme environmental conditions (Fernández Zenoff et al, 2006). In one such study, a novel A. johnsonii strain designated A2 was isolated from Andean wetlands and was found to be significantly more resistant to UV-B than A. johnsonii ATCC 17909 T (Di Capua et al, 2011), which we also observed to be very sensitive to UV-C radiation. Our observation that A. radioresistens is highly UV-C resistant compared with other Acinetobacter strains is consistent with previous findings that A. radioresistens is four-to eightfold more resistant to gamma radiation (Saha & Chopade, 2009) and~28-fold more resistant to ionizing radiation (Nishimura et al, 1994) than a limited set of other Acinetobacter strains, although the range of difference in survival was significantly greater (~300 000 fold) in this study than in these previous works.…”

Section: Resultsmentioning

confidence: 99%

Diverse responses to UV light exposure in Acinetobacter include the capacity for DNA damage-induced mutagenesis in the opportunistic pathogens Acinetobacter baumannii and Acinetobacter ursingii

et al. 2012

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Error-prone and error-free DNA damage repair responses that are induced in most bacteria after exposure to various chemicals, antibiotics or radiation sources were surveyed across the genus Acinetobacter. The error-prone SOS mutagenesis response occurs when DNA damage induces a cell's umuDC-or dinP-encoded error-prone polymerases. The model strain Acinetobacter baylyi ADP1 possesses an unusual, regulatory umuD allele (umuDAb) with an extended 59 region and only incomplete fragments of umuC. Diverse Acinetobacter species were investigated for the presence of umuDC and their ability to conduct UV-induced mutagenesis. Unlike ADP1, most Acinetobacter strains possessed multiple umuDC loci containing either umuDAb or a umuD allele resembling that of Escherichia coli. The nearly omnipresent umuDAb allele was the ancestral umuD in Acinetobacter, with horizontal gene transfer accounting for over half of the umuDC operons. Despite multiple umuD(Ab)C operons in many strains, only three species conducted UV-induced mutagenesis: Acinetobacter baumannii, Acinetobacter ursingii and Acinetobacter beijerinckii. The type of umuDC locus or mutagenesis phenotype a strain possessed was not correlated with its error-free response of survival after UV exposure, but similar diversity was apparent. The survival of 30 Acinetobacter strains after UV treatment ranged over five orders of magnitude, with the Acinetobacter calcoaceticus-A. baumannii (Acb) complex and haemolytic strains having lower survival than non-Acb or non-haemolytic strains. These observations demonstrate that a genus can possess a range of DNA damage response mechanisms, and suggest that DNA damage-induced mutation could be an important part of the evolution of the emerging pathogens A. baumannii and A. ursingii. INTRODUCTIONWhen bacteria are exposed to DNA-damaging agents, such as UV light or chemical mutagens, a wide variety of SOS response genes (genes that play critical roles in repairing damaged DNA) are specifically induced (Friedberg et al., 1995;Walker, 1996). In the model developed by experimentation in Escherichia coli, SOS genes are negatively regulated by the LexA repressor binding to the SOS box in the promoter (Mount et al., 1972). DNA damage causes the activation of RecA, which facilitates LexA self-cleavage and releases the repression of SOS genes such as umuDC (Little et al., 1980;1981). UmuD initially causes a pause in cell division while DNA repair and replication occurs (Opperman et al., 1999). However, within minutes, UmuD homodimerizes and carries out intermolecular self-cleavage, facilitated by activated RecA* interaction (Nohmi et al., 1988). Two cleaved UmuD9 molecules then associate with UmuC to form DNA polymerase V, which carries out error-prone, trans-lesion DNA replication (SOS mutagenesis) (Reuven et al., 1999;Tang et al., 1999). Another errorprone polymerase commonly involved in SOS mutagenesis as part of the DNA damage response is DinP (also called DinB), DNA polymerase IV, which can function either by itself (Kim et al., 1997) or with U...

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Section: Resultsmentioning

confidence: 99%

Diverse responses to UV light exposure in Acinetobacter include the capacity for DNA damage-induced mutagenesis in the opportunistic pathogens Acinetobacter baumannii and Acinetobacter ursingii

et al. 2012

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“…B. subtilis spores) [22], (ii) high catalase activity (Acinetobacter sp.) [9], (iii) sodium chloride concentrations in biofilm (Listeria monocytogenes) [3], (iv) biofilm formation (P. aeruginosa) [10], and (v) nucleotide excision repair by the uvrABC complex (Mycobacterium smegmatis) [19]. Considering the possibility that UV-tolerant bacteria could be present in the environment, such as P. aeruginosa, A. baumannii and B. cereus, as previously described, the pulsed UV radiation is a sufficient UV irradiation dose for disinfection of the environment.…”

Section: Environmental Disinfection Using Pulsed Uv Radiationmentioning

confidence: 97%

A Comparative Study of the Bactericidal Activity and Daily Disinfection Housekeeping Surfaces by a New Portable Pulsed UV Radiation Device

et al. 2012

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Daily cleaning and disinfecting of non-critical surfaces in the patient-care areas are known to reduce the occurrence of health care-associated infections. However, the conventional means for decontamination of housekeeping surfaces of sites of frequent hand contact such as manual disinfection using ethanol wipes are laborious and time-consuming in daily practice. This study evaluated a newly developed portable pulsed ultraviolet (UV) radiation device for its bactericidal activity in comparison with continuous UV-C, and investigated its effect on the labor burden when implemented in a hospital ward. Pseudomonas aeruginosa, Multidrug-resistant P. aeruginosa, Escherichia coli, Acinetobacter baumannii, Amikacin and Ciprofloxacin-resistant A. baumannii, Staphylococcus aureus, Methicillin-resistant S. aureus and Bacillus cereus were irradiated with pulsed UV or continuous UV-C. Pulsed UV and continuous UV-C required 5 and 30 s of irradiation, respectively, to attain bactericidal activity with more than 2Log growth inhibition of all the species. The use of pulsed UV in daily disinfection of housekeeping surfaces reduced the working hours by half in comparison to manual disinfection using ethanol wipes. The new portable pulsed UV radiation device was proven to have a bactericidal activity against critical nosocomial bacteria, including antimicrobial-resistant bacteria after short irradiation, and was thus found to be practical as a method for disinfecting housekeeping surfaces and decreasing the labor burden.

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“…However, pyocyanin showed no growth inhibition of A. baumannii (MIC Ͼ 18 mM), as it counteracted the pyocyanin-mediated oxidative stress by enhanced production of catalase and SOD. A. baumannii has been reported to combat H 2 O 2 -generated oxidative stress by increasing its catalase activity (32). Pyocyanin exerts oxidative stress on P. aeruginosa cells also, but it survives because of limited redox cycling of pyocyanin and increased levels of catalase and SOD (7).…”

Section: Discussionmentioning

confidence: 99%

Pyocyanin Stimulates Quorum Sensing-Mediated Tolerance to Oxidative Stress and Increases Persister Cell Populations in Acinetobacter baumannii

2014

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Acinetobacter baumannii and Pseudomonas aeruginosa are nosocomial pathogens with overlapping sites of infection. This work reports that the two can coexist stably in mixed-culture biofilms. In a study intended to improve our understanding of the mechanism of their coexistence, it was found that pyocyanin, produced by P. aeruginosa that generally eliminates competition from other pathogens, led to the generation of reactive oxygen species (ROS) in A. baumannii cells, which in response showed a significant (P < 0.05) increase in production of enzymes, specifically, catalase and superoxide dismutase (SOD). This work shows for the first time that the expression of catalase and SOD is under the control of a quorum-sensing system in A. baumannii. In support of this observation, a quorum-sensing mutant of A. baumannii (abaI::Km) was found to be sensitive to pyocyanin compared to its wild type and showed significantly (P < 0.001) lower levels of the antioxidant enzymes, which increased on addition of 5 M N-(3-hydroxydodecanoyl)-L-homoserine lactone. Likewise, in wild-type A. baumannii, there was a significant (P < 0.01) decrease in the level of anti-oxidant enzymes in the presence of salicylic acid, a known quencher of quorum sensing. In the presence of amikacin and carbenicillin, A. baumannii formed 0.07 and 0.02% persister cells, which increased 4-and 3-fold, respectively, in the presence of pyocyanin. These findings show that pyocyanin induces a protective mechanism in A. baumannii against oxidative stress and also increases its persistence against antibiotics which could be of clinical significance in the case of coinfections with A. baumannii and P. aeruginosa.

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UV-resistant Acinetobacter sp. isolates from Andean wetlands display high catalase activity

Cited by 42 publications

References 40 publications

Diverse responses to UV light exposure in Acinetobacter include the capacity for DNA damage-induced mutagenesis in the opportunistic pathogens Acinetobacter baumannii and Acinetobacter ursingii

Diverse responses to UV light exposure in Acinetobacter include the capacity for DNA damage-induced mutagenesis in the opportunistic pathogens Acinetobacter baumannii and Acinetobacter ursingii

A Comparative Study of the Bactericidal Activity and Daily Disinfection Housekeeping Surfaces by a New Portable Pulsed UV Radiation Device

Pyocyanin Stimulates Quorum Sensing-Mediated Tolerance to Oxidative Stress and Increases Persister Cell Populations in Acinetobacter baumannii

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