This preprint is under consideration at Annals of Clinical Microbiology and Antimicrobials. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
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Reza Ranjbar
Corresponding Author
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Background
Klebsiella pneumoniae is armed with a wide range of antibiotic resistance mechanisms which mostly challenges effective treatment. Due to this fact, the aims of the current study were to identify the clinical strains of K . pneumoniae as well as to determine their phenotypes and molecular characterization related to antimicrobial resistance and virulence genes.
Methods
In this investigation, specimens from a hospital and different laboratories located in Shahr-e-Qods, Tehran, Iran were collected during a period of nine-month (December 2018 to August 2019). The isolated strains of K. pneumoniae were then identified through standard microbial and biochemical assays. Additionally, disk diffusion, combined disk, modified Hodge test and PCR were performed for antibiotic resistance of the strains and virulence genes profiling, respectively. The molecular typing was accomplished by ERIC-PCR.
Results
Eighty-four isolates of K. pneumoniae were identified and subjected to the study. Fifty- two percent of the isolated strains of K. pneumoniae were detected as multidrug resistant (MDR) pathotypes with the highest resistance to ceftriaxone (65%) and the lowest resistance to colistin (23%). Twenty-seven (52%) out of 52 (100%) MDR pathotypes of isolated K. pneumoniae were identified as ESBL producers. According to Modified Hodge Test (MHT) results, out of 24 resistant strains of isolated K. pneumoniae to imipenem and meropenem, 15 pathotypes (62.5%) were detected as KPC producers. The gene of blaCTX (encoding carbapenemase) with 96% ranked first, while the blaKPC gene with the prevalence of 71% ranked second among ESBL producers. The aminoglycoside resistance gene of Aac6-Ib showed the highest frequency with the prevalence percentage of 90%. The virulence genes of mrkD (94%) and magA (11%) were the highest and lowest among isolates, respectively. According to ERIC-PCR results the isolated strains of K. pneumoniae were divided into four clusters in which the cluster 4 was predominant group.
Conclusions
The high prevalence of antibiotic resistance and virulence genes in conjunction with a significant relationship between the strains reveals a high pathogenic capacity of the isolated pathotypes of K. pneumoniae . These findings emphasize the choose of more effective antibiotic regimens for treatment of infections caused by K. pneumoniae.
Keywords: Klebsiella pneumoniae , antibiotic resistance, ESBL, virulence genes, molecular typing.
Keywords
Klebsiella pneumoniae, antibiotic resistance, ESBL, virulence genes, molecular typing
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Received 04 Apr, 2021
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On 26 Mar, 2021
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Received 26 Mar, 2021
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On 25 Mar, 2021
Editor invited
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Subject Areas
General Microbiology
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This preprint is under consideration at Annals of Clinical Microbiology and Antimicrobials. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Research
Reza Ranjbar
Corresponding Author
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Under Review
Version 1
Posted 26 Mar, 2021
No community comments so far
Review #1 received
Received 04 Apr, 2021
Reviewer #2 agreed
On 27 Mar, 2021
Reviewer #1 agreed
On 26 Mar, 2021
Review #? received
Received 26 Mar, 2021
Reviewers invited
Invitations sent on 26 Mar, 2021
Editor assigned
On 25 Mar, 2021
Editor invited
On 25 Mar, 2021
Submission checks complete
On 25 Mar, 2021
First submitted
On 15 Mar, 2021
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
General Microbiology
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background
Klebsiella pneumoniae is armed with a wide range of antibiotic resistance mechanisms which mostly challenges effective treatment. Due to this fact, the aims of the current study were to identify the clinical strains of K . pneumoniae as well as to determine their phenotypes and molecular characterization related to antimicrobial resistance and virulence genes.
Methods
In this investigation, specimens from a hospital and different laboratories located in Shahr-e-Qods, Tehran, Iran were collected during a period of nine-month (December 2018 to August 2019). The isolated strains of K. pneumoniae were then identified through standard microbial and biochemical assays. Additionally, disk diffusion, combined disk, modified Hodge test and PCR were performed for antibiotic resistance of the strains and virulence genes profiling, respectively. The molecular typing was accomplished by ERIC-PCR.
Results
Eighty-four isolates of K. pneumoniae were identified and subjected to the study. Fifty- two percent of the isolated strains of K. pneumoniae were detected as multidrug resistant (MDR) pathotypes with the highest resistance to ceftriaxone (65%) and the lowest resistance to colistin (23%). Twenty-seven (52%) out of 52 (100%) MDR pathotypes of isolated K. pneumoniae were identified as ESBL producers. According to Modified Hodge Test (MHT) results, out of 24 resistant strains of isolated K. pneumoniae to imipenem and meropenem, 15 pathotypes (62.5%) were detected as KPC producers. The gene of blaCTX (encoding carbapenemase) with 96% ranked first, while the blaKPC gene with the prevalence of 71% ranked second among ESBL producers. The aminoglycoside resistance gene of Aac6-Ib showed the highest frequency with the prevalence percentage of 90%. The virulence genes of mrkD (94%) and magA (11%) were the highest and lowest among isolates, respectively. According to ERIC-PCR results the isolated strains of K. pneumoniae were divided into four clusters in which the cluster 4 was predominant group.
Conclusions
The high prevalence of antibiotic resistance and virulence genes in conjunction with a significant relationship between the strains reveals a high pathogenic capacity of the isolated pathotypes of K. pneumoniae . These findings emphasize the choose of more effective antibiotic regimens for treatment of infections caused by K. pneumoniae.
Keywords: Klebsiella pneumoniae , antibiotic resistance, ESBL, virulence genes, molecular typing.
Figure 1
Figure 2
Figure 3
Figure 4
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