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Background: Gram-negative organisms producing Extended-spectrum beta-lactamases (ESBLs) are presented as a global problem. Klebsiella pneumoniae is considered as one of the most important microorganism of this group. The prevalence rate of K. pneumoniae species is increasing, and this increase is higher in the ESBL group, indicating the increase in antibiotic resistance. We must have sufficient knowledge about regional antibiotics resistance in order to monitor the prevalence rate and antimicrobial resistance among the isolates by appropriate treatment. In this regard, the objective of our study was to evaluate antimicrobial susceptibility among K. pneumoniae isolates by E-test method in Khatam ol Anbia hospital during 2015.
Materials and methods: This descriptive cross-sectional study was carried out during 2015.  All clinical samples were collected from intensive care unit (ICU) and general wards of Khatam ol Anbia hospital. All of the K. pneumoniae strains were detected by biochemical and microscopic tests. Antimicrobial susceptibility and minimum inhibitory concentration (MIC) were determined by disk diffusion and E-test methods. Descriptive statistics was used to analyze data.
Results: About 62 K.  pneumoniae strains were isolated from clinical samples of ICU and general wards during one year. Of these, 38 (61.3%) isolates were isolated from intensive care unit, and 24 (38.7%) isolates were isolated from the general wards. In this review, the least resistance was related to colistin (4.8%) and Amikacin (14.5%), respectively, and the most resistance was observed to the antibiotics of ciprofloxacin (66.1%), ceftriaxone (62.9%) and gentamicin (59.7%), respectively. Resistance to imipenem was observed in 38.7% of the isolates.
Conclusion: The current study demonstrates that antibiotic resistance pattern is changing, and resistance to imipenem and colistin is rising, so this should be considered as a serious risk for admitted patients in hospital.  

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Background: Klebsiella pneumoniae (K. pneumoniae) causes a wide range of nosocomial and community-acquired infections. In recent decades, K. pneumoniae has been known as the agent of community-acquired primary pyogenic liver abscess. In attempts to find the causes of this disease, researchers found a new virulence gene called magA (mucoviscosity-associated gene A). The present study was performed to determine the prevalence rate of magA gene among the extended-spectrum beta lactamase (ESBL)-positive and ESBL-negative K. pneumoniae strains.
Materials and Methods: The current cross-sectional study was conducted on 130 K. pneumoniae isolates collected from patients in Imam Reza hospital and its associated clinics in Mashhad city (Iran) from May 2011 to July 2012. The presence of K. pneumoniae species was confirmed by conventional microbio­logical methods.  Samples were tested for the production of ESBLs by the double disk diffusion (DDS) test. PCR was performed to detect magA gene. The hypermucoviscosity (HV) phenotype of Klebsiella isolates was char­acterized by the string test.
Results: magA gene was detected in 11(8.5%) out of 130 isolates of K. pneu­moniae. Of 11 isolates with positive result for magA gene, three cases were HV⁺, and 8 cases were HV^- phe­notype. Of 130 K. pneu­moniae isolates, 56 isolates were ESBL-positive, and 74 isolates were ESBL-negative. The magA gene was detected in 4 out of 56 (7.14%) ESBL-positive, and 7 out of 74 (9.46%) ESBL-negative samples.
Conclusion: In the present study, no correlation was observed between the presence of magA gene and the production of ESBL in K. pneumoniae strains isolated from different clinical samples in Mashhad. 

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Background: Klebsiella pneumoniae is a Gram-negative bacterium and a part of the natural microflora of gastrointestinal tract in human body. K. pneumoniae has been known as one of the most common cause of nosocomial infections and multi-drug resistance pathogen. The aims of this study was to examine the detection of antimicrobial susceptibility and genetic relatedness among K. pneumoniae strains isolated from hospitals in Borujerd in western Iran using Enterobacterial Repetitive Intergenic Consensus (ERIC)–PCR technique.
Materials and Methods: A total of 100 K. pneumoniae isolates were collected from Borujerd hospitals from April to September 2015. After detection and confirmation of K. pneumoniae isolates by conventional laboratory methods and differential tests, antibiotic susceptibility was detected by disk diffusion method. Also, genetic relatedness of 34 selected MDR K. pneumoniae isolates were investigated by ERIC - PCR technique.
Results: Antibiotic susceptibility testing showed that among K. pneumoniae isolates, the highest antibiotic resistance was observed in ampicillin (91%) and the highest susceptibility was detected in imipenem (5.5%). More than 45% of isolates showed multi resistant phenotypes. Based on ERIC-PCR results, 31 different ERIC types were detected.
Conclusion: The results of this study indicate the increase of multi resistance K. pneumoniae in hospitals under study. The results of ERIC PCR showed high genetic diversity among K. pneumoniae strains, which indicated the poly clonal distribution of K. pneumoniae isolates in Borujerd hospitals.

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Aims: There are few data regarding the prevalence and trends of Klebsiella pneumoniae antibiotic resistance in Algeria. The present study was conducted to investigate the spatial distribution of K. pneumoniae antibiotic resistance phenotypes in time and according to specimen source.   
Materials & Methods: This retrospective study was performed between January 2011 and December 2015 at Mila Hospital, Algeria. A total of 172 K. pneumoniae were isolated from consulting and hospitalized patients, and their antimicrobial susceptibility was tested. The Principal Component Analysis (PCA) was used to study correlations among antimicrobial resistance phenotypes observed, and Factorial Correspondence Analysis (FCA) was used to study the spatial distribution of antibiotic resistance phenotypes according to specimen source.
Findings: The specimens were obtained from urine (n=89), vagina (n=39), pus (n=33), blood (n=9) and surgery (n=2). PCA showed two principals associations of resistance phenotypes gathered in two clusters. The first profile regroups amoxicillin-clavulanic acid, cefazolin and ampicillin. The second assembles cefotaxime, nalidixic acid and sulfamethoxazole-trimethoprim. In FCA, nalidixic acid was connected with urine specimens, registering maximum resistance (52.8%) compared to the other samples. Vagina specimens were associated to sulfamethoxazole-trimethoprim and colistin phenotypes registering maximum resistances with 89.7 and 76.9%, respectively. Pus manifested a near association to cefotaxime with a maximum resistance (48.5%).
Conclusion: The model developed in FCA, highlights typical associations of antibiotic resistance phenotypes to specimen source and confirms the difference in resistance profile according the source of specimen in K. pneumoniae infections.

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Aims: 16S ribosomal RNA methyltransferases (RMTases) confer high-level resistance to aminoglycosides and are increasingly reported among Gram-negative bacilli, especially Klebsiella pneumoniae isolates. The objectives of the present study were to assess the resistance to aminoglycosides, the presence of RMTase genes, and the multilocus sequence typing (MLST) in urinary K. pneumoniae isolates.
Materials & Methods: In this study, 100 K. pneumoniae isolates were tested for susceptibility to amikacin and gentamicin by broth microdilution test according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Then the prevalence of RMTase genes was determined, and alleles and ST type of two selected isolates were identified by MLST. Finally, the isolates were genetically typed using Enterobacterial Repetitive Intergenic Consensus (ERIC) method.
Findings: Broth microdilution assay showed that resistance to amikacin and gentamicin was 70 and 52%, respectively. In addition, 40% of the strains were resistant to both aminoglycosides. Also, rmtC (59.8%) gene was the most common type of RMTase genes investigated, followed by rmtA (51.2%), rmtD (47.6%), rmtF (43.9%), rmtE (41.5%), armA (41.5%), and rmtB (7.3%). K. pneumoniae isolates were assigned into two sequence types: ST51 and ST149. Using ERIC-PCR method, 3-7 different bands and 21 ERIC-PCR profiles were detected among the studied isolates.
Conclusion: The high frequency of aminoglycoside resistance and the increased presence of 16S RMTases in K. pneumoniae strains are of great concern in Iran. Molecular typing showed high genetic diversity among the studied isolates. However, ST51 and ST149 were reported for the first time in Iran and could be considered as emerging strains.

 

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Background: This study aimed to investigate the biofilm formation ability of K. pneumoniae clinical isolates using phenotypic and genotypic methods. Additionally, the association of biofilm formation with antibiotic resistance and the presence of biofilm-related genes was investigated.
Materials & Methods: In this research, a total of 52 clinical isolates of K. pneumoniae were collected from educational hospitals affiliated with Babol University of Medical Sciences from March to October 2023. K. pneumoniae isolates were identified through standard microbiological and biochemical tests. Disk diffusion, microtiter plate, and polymerase chain reaction assays were also performed to evaluate the biofilm formation ability of these isolates.
Findings: K. pneumoniae isolates were obtained from various clinical specimens. The isolates showed the highest resistance to ceftazidime (54%) and the lowest resistance to amikacin (17%). More than 48% of the isolates were multidrug resistant. Of the 52 K. pneumoniae isolates, 43 (82.69%) isolates produced biofilm, whereas the remaining nine (17.3%) did not. K. pneumoniae isolates harbored biofilm formation genes, including treC (78.84%), wcaG (71.15%), mrkD (65.38%), mrkA (63.46%), iutA (40.38%), and magA (15.38%).
Conclusion: This study demonstrates that K. pneumoniae isolates are highly pathogenic because of antibiotic resistance and carrying biofilm genes. Given the biofilm formation propensity of these strains, it is imperative to elucidate the underlying mechanisms of biofilm formation in K. pneumoniae. Developing strategies to inhibit this process is paramount in the effective management of infections caused by this pathogen.

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Background: Klebsiella pneumoniae (K. pneumoniae) is responsible for life-threatening infections, given that it is usually resistant to antibacterial drugs. Due to the restricted antibiotic options for the treatment of resistant K. pneumoniae infections and the critical role of humoral immune responses in preventing infectious diseases, the present in silico study aimed to investigate fimbriae (type 1 and type 3), outer membrane protein A (OmpA), and outer membrane protein K35 (OmpK35) to find appropriate epitopes for vaccine development.
Materials & Methods: Several independent bioinformatics servers including IEDB, ABCpred, VaxiJen, and EMBOSS were applied to identify appropriate linear epitopes (B-cell and T-cell).  Conformational epitopes were also predicted using Ellipro and Discotope programs. The Antigenic Peptide Prediction server was used to confirm the identified epitopes. Molecular characteristics, toxicity, human similarity, and allergenicity were investigated.
Findings: The results demonstrated that the investigated proteins were highly immunogenic. In the first step, 25 epitopes were identified in the investigated proteins. After applying different exclusion criteria, the final epitope of each investigated protein was selected. The final epitopes of fimbriae (type 1 and type 3), OmpK35 and OmpA were located in 28-49, 26-53, 271-291, and 288-299 regions, respectively. Allergenicity, toxicity, and human similarity were negative for the predicted epitopes.
Conclusion: The present study results introduced four reliable B-cell and T-cell epitopes (each for one investigated protein) with appropriate physicochemical characteristics. The proposed epitopes could be used in vaccine development against K. pneumoniae after further in vitro and in vivo studies.

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Klebsiella pneumoniae is a gram-negative bacillus of the Enterobacteriaceae family. Despite being part of the natural human microflora, this is an opportunistic pathogen and a major cause of nosocomial infections. The increased emergence of multidrug resistance in Klebsiella pneumoniae has limited the treatment options for this bacterium. Carbon nanotubes (CNT), by improving the stability and solubulity of drugs, could increase the effectiveness of drugs for treatment. The aim of this study is to investigate the antibacterial effect of nanofluid containing functionalized multi-walled carbon nanotubes (f-CNT-NF) on Klebsiella pneumoniae isolated from clinical specimens. For the strain confirmation, biochemical ,API20E kit, and additional differential tests were performed, and antibiotic susceptibility test was performed by the disk diffusion method. The studied strain showed a resistance to all antibiotics such as cefepime.The minimum inhibitory concentration (MIC) was determined using the antibiotic micro dilution method. The MIC was determined in five effect modes including antibiotic (Ab), nanofluid containing functionalized multi-walled carbon nanotubes (f-CNT-NF) , nanofluid containing multi-walled carbon nanotubes (CNT-NF) ,Ab in combination with f-CNT-NF and Ab with CNT-NF. Nevertheless the individual effects of 10 µg mL^-1 cefepime or 80 µg of nanofluid with f-CNT-NF did not inhibit the growth of the bacteria, but the co-administration of 10 µg mL^-1 cefepime with 80 µg of the f-CNT-NF could inhibit the bacteria`s growth. It was concluded that f-CNT-NF could be more effective in drug delivery at lower concentrations than the free state, which could be used as a tool for optimal drug delivery.