Acinetobacter poses very little risk to healthy people. People who have weakened immune systems, chronic lung disease, or diabetes are more susceptible to Acinetobacter infection. Hospitalized patients, especially those who are very ill, have open wounds, have an invasive device, are on ventilators, or are in the hospital for a long time are also at greater risk for Acinetobacter infection.
Acinetobacter is spread by contact with a person or environment that has the bacteria. Symptoms of Acinetobacter infection can appear from 4—40 days after exposure to the bacteria, but usually appear within about 12 days. Commonly prescribed antibiotics often do not work to treat Acinetobacter. Conjugation experiments were conducted to determine transmissibility of resistance. Pulsed-field gel electrophoresis and whole genome sequencing were performed to identify strain-specific features.
The isolate XM was identified as Acinetobacter calcoaceticus. Whole genome sequencing identified two plasmids, pXM1 and pXM2. Plasmid pXM1 carried the carbapenemase gene bla NDM-1 and displayed high homology with previously described plasmids isolated from different Acinetobacter spp. Transferability of resistance from pXM1 to the transconjugants was identified. A chromosomally located carbapenemase-encoding gene bla OXA was detected; however, this gene was interrupted by an insertion sequence IS Aba22 belonging to IS3 family.
Location of bla NDM-1 on different self-transmissible plasmids could facilitate geographically broad dissemination and host range expansion of the bla NDM-1 gene via horizontal gene transfer. Our findings of this normally environmental species A. The online version of this article doi The plasmid-located carbapenem resistance gene bla NDM-1 was first detected in Klebsiella pneumoniae [ 5 ].
The gene, often flanked by mobile genetic elements, is now one of the most widespread carbapenemases genes and has been detected worldwide in multiple Gram-negative bacterial species including Acinetobacter spp.
Globalization and international travel accelerates the rapid dissemination of NDM-1 producers between different countries and continents [ 7 ]. Since the first report of a bla NDM-1 positive A. In only four A. More recently studies have reported high isolation rates of bla NDM-1 -containing bacteria from clinical fecal samples and the sewage of hospitals [ 13 , 14 ]. Of concern was the reported identification of 27 Acinetobacter spp.
Surveys of the bla NDM-1 gene in bacteria of food animal origin also recovered two positive strains, A. The bla NDM-1 gene was found to be located on different plasmids which are easily transferable and capable of rearrangement [ 18 ].
Several bla NDM-1 -harboring plasmids have been reported to be indistinguishable from or highly related to the plasmid pNDM-BJ01 which has been previously isolated from clinical A. The bla NDM-1 gene was found to be flanked by two copies of IS Aba and this common surrounding genetic structure of bla NDM-1 were shared in most of the non- baumannii Acinetobacter spp. Although it is not clear how the bla NDM-1 gene has emerged and spread across China, the diversity of bla NDM-1 harboring species recovered from different locations and the repeated occurrence of pNDM-BJlike plasmids are unlikely to be a coincidence [ 19 ].
To our knowledge, no NDMharboring A. Here we describe the detection and genetic characterization of a bla NDM-1 harboring A. During routine sentinel surveillance, we isolated a bla NDM-1 -harboring bacterial strain from a patient died of pneumonia and respiratory failure.
The isolate was positive for the bla NDM-1 gene and identified as A. Other 22 Acinetobacter spp. Samples were collected as part of standard patient care. Informed consent was not obtained except included patients were subjected to extra procedures. Collection of all samples in this study was approved by the ethics committee of the Academy of Military Medical Sciences China.
The Dice coefficient of similarity was calculated with a position tolerance of 1. Antimicrobial susceptibility testing of all isolates was determined by using disk diffusion method. The E-test strips were used as necessary to determine the MICs of certain antibiotics such as imipenem. The above results were interpreted according to the Clinical and Laboratory Standards Institute guidelines [ 29 ]. Conjugative experiments were performed using E. The whole genome of A. Protein sequences of 18 Acinetobacter spp.
Those conserved proteins were then concatenated and aligned by ProbCons with default options [ 31 ]. PhyML 3. The tree was bootstrapped times to estimate the confidence of tree topologies.
To further assess genome structure and rearrangement, sequences of XM were compared with the only finished genome of A. All isolates were identified as Acinetobacter spp.
Isolate and were further identified as A. PFGE was performed to investigate the population structure of the Acinetobacter isolates. However, the profile of antimicrobial susceptibility was quite different between these two isolate. Most of other isolates also displayed multidrug resistances, eleven of which also showed resistance or intermediate resistance to imipenem.
PFGE-based dendrogram and antimicrobial resistance profile of the 23 isolates from the same hospital in Xiamen, Fujian, China. The dendrogram was constructed based on unweighted pair-group method using average linkages and pairwise Dice coefficients.
Antimicrobial susceptibility was performed by disk fusion, black indicates resistance; gray indicates intermediate; white indicates susceptible. Clostridium difficile, now called Clostridioides difficile C. MRSA is an infection that is resistant to certain antibiotics, including penicillin, which makes it challenging to treat.
Find out what it is and why…. Acinetobacter: What to know. Medically reviewed by Jill Seladi-Schulman, Ph. Infection and symptoms Types Treatment Prevention Transmission Summary Acinetobacter is a type of bacteria that is resistant to many types of antibiotics.
Infection and symptoms. Share on Pinterest A person with a blood infection may experience a fever. Latest news Adolescent depression: Could school screening help?
Exposure to air pollutants may amplify risk for depression in healthy individuals. Related Coverage. Superbugs: Everything you need to know. What to know about antibiotics. Medically reviewed by Alan Carter, PharmD. What are the side effects of antibiotics? What to know about Clostridium difficile. The PFGE results were consistent with the MLST results, the strains with the same pulsotype presented the same ST, and except for the strains with pulsotypes 17 and 21, which were related despite being associated with different patients and years.
The pulsotypes 17 and 21were grouped with the same restriction patterns; nevertheless, we could observe that they differed with respect to their resistance profile, plasmid profile, and amplification of bla OXA genes. However, the determination of different STs allows us to suggest that these pulsotypes group different strains; the opposite occurred in some of the strains that were isolated from different patients, since there were cases in which, according to the agreement of the data obtained by PFGE, the same patient could harbor different pulsotypes; nevertheless, they could present the same ST P14, and P Recently, the polymorphism observed between CRISPR-Cas systems has been used to genotype strains and establish phylogenetic relationships in different bacterial species; although, in some cases the spacers can be too diverse, hindering their use as a method for subtyping.
The use of this system has also separated other bacteria such as Erwinia amylovora into different groups depending on their geographical origin Rezzonico et al.
Two systems have been described in A. Despite the successful implementation of the CRISPR-Cas system as a typing method in other studies, we were unable to use it because not all of the strains had this system; however, two phenomena were observed.
According to Mangas et al. The gene encoding the Cas1 protein is one of the most conserved and is involved in the acquisition of spacers and it has been proposed that the gene evolves slower than other cas genes Takeuchi et al.
The strains that amplified this gene did not amplify any CRISPR-Cas system, so we could suggest the presence of another system different from those sought in this study.
In contrast, 26 strains amplified at least one system but not the cas gene. However, it is necessary to carry out other studies to demonstrate this hypothesis. The detection of these systems through PCR and amplification sequencing seems to be simple; however, something that must be highlighted is the probable implication of these systems in other processes. In the case of patients, there were two interesting conditions. First, in patients 14, 20, 27, 28, 37, 43, and 47 , more than one strain was isolated, some with differences of days or 1 month.
These strains were all different, locating themselves into different pulsotypes, STs, and with differences in the rest of the characteristics evaluated, suggesting the presence of different strains in the same patient over a short temporality. In the second case, was observed that patients 11, 16, and 19 had more than one strain; however, they were divided into two groups in the same patient that were identical, and that were not same in the characteristics evaluated, suggesting once again the presence of more than one strain over a longer period.
In 11 patients, the strains were obtained on the same date but corresponded to different samples, presenting cases, in which the strains showed the same characteristics with respect to the pulsotype, bla OXA-LIKE genes, plasmid profile, and type sequence.
Nevertheless, five patients P16, P18, P27, P30, and P47 provided samples on the same date but with phenotypic and genotypic characteristics that were completely different. Also, there were cases presented in which the samples obtained more than 1 day apart exhibited the same characteristics.
Only 17 strains were associated with HAIs, such as bacteremia and pneumonia. The strains were distributed along the tree and only clustered when they were from the same patient such as pulsotypes 2 and 25, for which all of the phenotypic and genotypic characteristics were identical, with the exception of strain BC recovered from the patient 52, the only difference that had with the other two strains BC and BC isolated of this patient was his macrorestriction pattern.
Patients 18 BC and 38 BC developed bacteremia; while, patients 37 D , 43 BC , and 45 BC developed pneumonia, the strains were randomly distributed in different pulsotypes, but apparently there was no related between them. Interestingly, these features were observed for strains identified as A. The latter was isolated together with two strains of A. These strains were collected from a total of 10 patients and are genetically diverse since they presented different plasmid profiles, type sequences, and pulsotypes.
According to the results obtained in this study, an increase was identified an increase in the number of resistant carbapenems strains. The molecular typing methods allowed us to determine the relationships between clinical strains.
PFGE data demonstrated that different patients could be infected by the same strain identical pulsotypes were harbored by more than one patient. MLST showed that the strains in one group, i. The severity of the disease and the difference between strains that are closely related to those associated with HAIs shown in this study, were related to the immunocompromise patient and virulence factors of the strain, which were not determined in this study and will be examined in a future study.
The clinical importance of A. Therefore, it is necessary to identify and differentiate the species in the Acb complex to determine their epidemiological and clinical importance. The implementation of molecular epidemiology allows the characterization of a set of strains and identification of different attributes associated with their distribution in a specific environment.
This study will allow future interventions for the recognition of risk factors related to opportunistic pathogens such as A. The datasets presented in this study can be found in online repositories. The Research Committee Dr. Written informed consent was not required for this study according to the institutional ethical, biosecurity and investigation committees because the Central Laboratory from the HIMFG provided the A.
JM-R done the experiments. DR-Z reviewed the clinical data. IP-O supplied the A. MC-C carried out susceptibility. All authors contributed to the article and approved the submitted version. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Molecular mechanisms associated with nosocomial carbapenem-resistant Acinetobacter baumannii in Mexico.
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