Molecular characterization, serotypes and phenotypic and genotypic evaluation of antibiotic resistance of the Klebsiella pneumoniae strains isolated from different types of hospital-acquired infections

Novel Antibacterial Agents SAAP-148 and Halicin Combat Gram-Negative Bacteria Colonizing Catheters

The antibiotic management of catheter-related infections (CRIs) often fails owing to the emergence of antimicrobial-resistant strains and/or biofilm/persister apparitions. Thus, we investigated the efficacy of two novel antimicrobial agents, i.e., the synthetic peptide SAAP-148 and the novel antibiotic halicin, against Gram-negative bacteria (GNB) colonizing catheters. The antibacterial, anti-biofilm, and anti-persister activities of both agents were evaluated against Acinetobacter baumannii, Escherichia coli, and Klebsiella pneumoniae strains. The enrolled strains were isolated from catheters and selected based on their resistance to at least three antibiotic classes and biofilm formation potential. Furthermore, the hemolysis and endotoxin neutralization abilities of these agents were explored. The bactericidal activity of both agents was reduced in urine and plasma as compared to buffered saline. In a dose-dependent manner, SAAP-148 and halicin reduced bacterial counts in 24 h preformed biofilms on silicone elastomer discs and eliminated persisters originating from antibiotic-exposed mature 7-day biofilms, with halicin being less effective than SAAP-148. Importantly, SAAP-148 and halicin acted synergistically on E. coli and K. pneumoniae biofilms but not on A. baumannii biofilms. The peptide, but not halicin, decreased the production of IL-12p40 upon exposure to UV-killed bacteria. This preliminary study showed that SAAP-148 and halicin alone/in combination are promising candidates to fight GNB colonizing catheters.

Continuous infusion of meropenem-vaborbactam for a KPC-3-producing Klebsiella pneumoniae bloodstream infection in a critically ill patient with augmented renal clearance

PURPOSE

To demonstrate the feasibility of continuous infusion of meropenem-vaborbactam to optimize the treatment of carbapenem-resistant Enterobacterales.

METHODS

Report of a case of a Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae bloodstream infection comfirmed by whole genome sequencing and therapeutic drug monitoring (TDM) of meropenem.

RESULTS

A patient with augmented renal clearance (ARC) went into septic shock caused by an ST11 KPC-3-producing K. pneumoniae bloodstream infection that was successfully treated with a continuous infusion of meropenem-vaborbactam at a dosage of 1 g/1 g q4h as a 4-h infusion. TDM confirmed sustained concentrations of meropenem ranging from 8 to 16 mg/L throughout the dosing interval.

CONCLUSION

Continuous infusion of meropenem-vaborbactam was feasible. It could be appropriate for optimizing the management of critically ill patients with ARC, as it resulted in antibiotic concentrations above the minimum inhibitory concentration for susceptible carbapenem-resistant Enterobacterales (up to 8 mg/L) throughout the dosing interval.

Antibacterial and antibiofilm effects of green synthesized selenium nanoparticles on clinical Klebsiella pneumoniae isolates

Nanotechnology covers many disciplines, including the biological sciences. In this study, selenium nanoparticles (Se-NPs) were synthesized using Artemisia annua extract and investigated against clinical strains of klebsiella pneumoniae (K. pneumoniae) for their anti-biofilm effects. In this experimental study, from May 1998 to September 1998, 50 clinical samples of blood, urine, and sputum were collected, and K. pneumoniae strains were isolated using microbiological methods. Subsequently, the antibacterial effects of Se-NPs at concentrations of 12-25-50-100/5-6/3-25/125 μg/mL were studied. Finally, biofilm-producing strains were isolated, and the expression of mrkA biofilm gene was studied in real-time strains treated with Se-NPs using real-time polymerase chain reaction (PCR). Out of 50 clinical samples, 20 strains of K. pneumoniae were isolated. Minimum inhibitory concentration (MIC) results of Se-NPs showed that Se-NPs were capable of significant cell killing. Real-time PCR results also showed that mrkA gene expression was significantly reduced in strains treated with Se-NPs. According to this study, Se-NPs could reduce bacterial growth and biofilm formation, therefore, could be considered a candidate drug in the medical application for infections caused by K. pneumoniae.

Molecular Characterization of Antibiotic Resistance Determinants in Klebsiella pneumoniae Isolates Recovered from Hospital Effluents in the Eastern Cape Province, South Africa

Klebsiella pneumoniae (K. pneumoniae) is an opportunistic bacteria responsible for many nosocomial and community-acquired infections. The emergence and spread of antibiotic resistances have resulted in widespread epidemics and endemic dissemination of multidrug-resistant pathogens. A total of 145 K. pneumoniae isolates were recovered from hospital wastewater effluents and subjected to antibiogram profiling. Furthermore, the antibiotic resistance determinants were assessed among phenotypic resistant isolates using polymerase chain reaction (PCR). The isolates showed a wide range of antibiotic resistance against 21 selected antibiotics under 11 classes, with the most susceptible shown against imipenem (94.5%) and the most resistant shown against ampicillin (86.2%). The isolates also showed susceptibility to piperacillin/tazobactam (89.0%), ertapenem (87.6%), norfloxacin (86.2%), cefoxitin (86.2%), meropenem (76.6%), doripenem (76.6%), gentamicin (76.6%), chloramphenicol (73.1%), nitrofurantoin (71.7%), ciprofloxacin (79.3%), amikacin (60.7%), and amoxicillin/clavulanic acid (70.4%). Conversely, resistance was also recorded against tetracycline (69%), doxycycline (56.6%), cefuroxime (46.2%), cefotaxime (48.3%), ceftazidime (41.4%). Out of the 32 resistance genes tested, 28 were confirmed, with [tetA (58.8%), tetD (47.89%), tetM (25.2%), tetB (5.9%)], [sul1 (68.4%), sul1I (66.6%)], and [aadA (62.3%), strA (26%), aac(3)-IIa(aacC2)^a (14.4%)] genes having the highest occurrence. Strong significant associations exist among the resistance determinants screened. About 82.7% of the K. pneumoniae isolates were multidrug-resistant (MDR) with a multiple antibiotics resistance index (MARI) range of 0.24 to 1.0. A dual presence of the resistant genes among K. pneumoniae was also observed to occur more frequently than multiple presences. This study reveals a worrisome presence of multidrug-resistant K. pneumoniae isolates and resistance genes in hospital waste effluent, resulting in higher public health risks using untreated surface water for human consumption. As a result, adequate water treatment and monitoring initiatives designed to monitor antimicrobial resistance patterns in the aquatic ecosystem are required.

The Antibacterial Activity of Rhazya stricta Extracts against Klebsiella pneumoniae Isolated from Some Soil Invertebrates at High Altitudes

Klebsiella is a common dangerous pathogen for humans and animals and is widely present in the digestive system. The genus Klebsiella is ubiquitous, as it is endemic to surface water, soil, and sewage. In this study, 70 samples were obtained from soil-dwelling invertebrates from September 2021 to March 2022 from Taif and Shafa in different altitudinal regions of Saudi Arabia. Fifteen of these samples were identified as Klebsiella spp. The Klebsiella isolates were genetically identified as Klebsiella pneumoniae using rDNA sequencing. The antimicrobial susceptibility of the Klebsiella isolates was determined. Amplification of virulence genes was performed using PCR. In this study, 16S rDNA sequencing showed a similarity from 98% to 100% with related K. pneumonia from the NCBI database, and the sequences were deposited in the NCBI GenBank under accession numbers ON077036 to ON077050. The growth inhibition properties of ethanolic and methanolic extracts of the medicinal plant Rhazya stricta's leaves against K. pneumoniae strains using the minimum inhibitory concentration (MIC) method and disc diffusion were evaluated. In addition, the biofilm inhibitory potential of these extracts was investigated using crystal violet. HPLC analysis identified 19 components divided into 6 flavonoids, 11 phenolic acids, stilbene (resveratrol), and quinol, and revealed variations in the number of components and their quantities between extracts. Both extracts demonstrated interesting antibacterial properties against K. pneumoniae isolates. The 2 extracts also showed strong biofilm inhibitory activities, with percentages of inhibition extending from 81.5% to 98.7% and from 35.1% to 85.8% for the ethanolic and methanolic extracts, respectively. Rhazya stricta leaf extract revealed powerful antibacterial and antibiofilm activities against K. pneumoniae isolates and could be a good candidate for the treatment or prevention of K. pneumonia-related infections.

Detection of AcrA and AcrB Efflux Pumps in Multidrug-Resistant Klebsiella pneumonia that Isolated from Wounds Infection Patients in Al-Diwaniyah Province

Many infections produced by multidrug-resistant (MDR) Klebsiella pneumoniae are the main cause of death and treatment restrictions worldwide. In K. pneumoniae, the efflux pump system is dangerous in drug resistance. Therefore, this study was designed to investigate the involvement of the AcrA and AcrB efflux pumps in antibiotic resistance in Klebsiella pneumoniae isolated from wound patients. During June 2021-February 2022, 87 clinical isolates of Klebsiella pneumonia bacteria were obtained from wound samples patients consulted to the hospitals in AL-Diwaniyah province, Iraq. The disc diffusion method performed an antibiotic susceptibility test after microbiological/biochemical identification. The polymerase chain reaction (PCR) technique was used to examine efflux genes' prevalence (acrA and acrB). The results showed that resistance to Carbenicillin 72 (82.7%), Erythromycin 66 (75.8%), Rifampin 58 (66.6%), Ceftazidime 52 (59.7%), Cefotaxime 44 (50.5%), Novobiocin 38 (43.6%), Tetracycline 32 (36.7%), Ciprofloxacin 22 (25.2%), Gentamicin 16 (18.3%), Nitrofurantoin 6 (10.3%) in Klebsiella pneumoniae isolates. The PCR procedure revealed that the occurrence of the acrA and acrB genes is 55 (100%) and 55 (100%), respectively. The findings of this investigation show that the AcrA and AcrB efflux pumps play a crucial character in antibiotic resistance in multidrug-resistant Klebsiella pneumoniae bacterial isolates. As a result of the unintentional transmission of antimicrobial resistance genes, precise detection of resistance genes using molecular approaches is required to switch the extent of resistant strains.

Bacterial Resistance in Hospital-Acquired Infections Acquired in the Intensive Care Unit: A Systematic Review

PURPOSE

In this review we present the status of the prevalence of bacteria resistant to antibiotics and the main antibiotic resistance genes that are reported in infections acquired in intensive care units (ICU) around the world.

METHODS

A systematic review based on the PRISMA guide was carried out, from the Science Direct, Redalyc, Scopus, Hinari, Scielo, Dialnet, PLOS, ProQuest, Taylor, Lilacs and PubMed/Medline databases. Inclusion criteria of this review were original research study published in a scientific journal in a 10-year time span from 1 January 2017 and 30 April 2022.

RESULTS

A total of 1686 studies were identified, but only 114 studies were considered eligible for inclusion. Klebsiella pneumoniae and Escherichia coli resistant to carbapenems and producers of extended-spectrum β-lactamases (ESBL) are the most frequently isolated pathogens in ICUs in Asia, Africa and Latin America. The blaOXA and blaCTX were antibiotic resistance genes (ARG) most commonly reported in different geographic regions (in 30 and 28 studies, respectively). Moreover, multidrug-resistant (MDR) strains were reported in higher frequency in hospital-acquired infections. Reports of MDR strains vary between continents, with the majority of publications being in Asia and between countries, with Egypt and Iran being highlighted. There is a predominance of few bacterial clones with MDR phenotype, for example, clonal complex 5 Methicillin-Resistant Staphylococcus aureus (CC5-MRSA) circulates frequently in hospitals in the United States, clone ST23-K. pneumoniae is reported in India and Iran, and clone ST260 carbapenemase-producing P. aeruginosa in the United States and Estonia.

CONCLUSION

Our systematic review reveals that ESBL- and carbapenemase-producing K. pneumoniae and E. coli are the most problematic bacteria that are reported, mainly in tertiary hospitals in Asia, Africa, and Latin America. We have also found propagation of dominant clones with a high degree of MDR, becoming a problem due to its high capacity to cause morbidity, mortality and additional hospital costs.

High Frequency of blaOXA-48like Producing Klebsiella pneumoniae Isolated from Nosocomial Infection in Azerbaijan, Iran

BACKGROUND

Klebsiella pneumoniae is one of the significant agents of hospital-acquired infections. In recent years, carbapenem-resistant K. pneumoniae (CRKP) isolates have been found in numerous epidemics of nosocomial infections. This study aimed to determine carbapenem resistance mechanisms and molecular epidemiological of CRKP infections in Azerbaijan, Iran.

MATERIALS AND METHODS

A total of 50 non-duplicated CRKP from January 2020 to December 2020 were isolated form Sina and Imam Reza Hospitals in Tabriz, Iran. Antimicrobial susceptibility testing was performed by the disk-diffusion method. The carbapenem resistance mechanisms were determined by the phenotypic and PCR procedures. CRKP isolates were typed by the Random Amplified Polymorphic DNA PCR (RAPD-PCR) technique.

RESULTS

Amikacin was the most effective antibiotics against CRKP isolates. AmpC overproduction was observed in five CRKP isolates. Efflux pump activity was found in one isolate by the phenotypic method. Carba NP test could find carbapenemases genes in 96% of isolates. The most common carbapenemases gene in CRKP isolates were bla_OXA-48-like (76%) followed by bla_NDM (50%), bla_IMP (22%), bla_VIM (10%), and bla_KPC (10%). The outer membrane protein genes (OmpK36 and OmpK35) were identified in 76% and 82% of CRKP isolates, respectively. RAPD-PCR analysis yielded 37 distinct RAPD-types. Most bla_OXA-48-like positive CRKP isolates were obtained from patients hospitalized in intensive care unit (ICU) wards with urinary tract infections.

CONCLUSION

The bla_OXA-48-like is the main carbapenemase among CRKP isolates in this area. Most bla_OXA-48-like producer CRKP strains were collected from the ICU ward and urine samples. To control infections due to CRKP, a strict control program in hospital settings is required.

Phenotypic and genotypic detection of carbapenemase-producing Escherichia coli and Klebsiella pneumoniae in Accra, Ghana

AIM

To describe the occurrence of carbapenem resistance among multidrug-resistant (MDR) Escherichia coli and Klebsiella pneumoniae isolated from clinical specimens in Accra using phenotypic and genotypic methods.

METHODOLOGY

The study was cross-sectional, involving 144 clinical MDR E. coli and K. pneumoniae isolates recovered from the Central Laboratory of the Korle Bu Teaching Hospital (KBTH). The isolates were re-cultured bacteriologically, identified using standard biochemical tests, and subjected to antibiotic susceptibility testing using the Kirby-Bauer method. Carbapenem resistance was determined based on imipenem, meropenem, and ertapenem zones of inhibition, as well as minimum inhibitory concentrations (MICs). Carbapenemase production was determined phenotypically by modified Hodge test (MHT) and modified carbapenem inactivation method (mCIM), and genotypically with multiplex PCR targeting the blaKPC, blaIMP, blaNDM, blaVIM, and blaOXA-48 genes.

RESULTS

Of the 144 MDR isolates, 69.4% were E. coli, and 30.6% were K. pneumoniae. The distribution of antimicrobial resistance rates among them was ampicillin (97.2%), cefuroxime (93.1%), sulfamethoxazole-trimethoprim (86.8%), tetracycline (85.4%), cefotaxime and cefpodoxime (77.1% each), amoxicillin-clavulanate (75%), ceftriaxone (73.6%), ciprofloxacin (70.8%), levofloxacin (66.0%), cefepime (65.3%), ceftazidime (64.6%), gentamicin (48.6), piperacillin-tazobactam (40.3%), cefoxitin (14.6%), amikacin (13.9%), ertapenem and meropenem (5.6% each), and imipenem (2.8%). In total, 5.6% (8/144) of them were carbapenem-resistant (carbapenem MIC range = 0.094-32.0 μg/ml), with 75% (6/8) of these testing positive by the phenotypic tests and 62.5% (5/8) by the genotypic test (of which 80% [4/5] carried blaOXA-48 and 20% (1/5) blaNDM). The blaVIM, blaIMP, and blaKPC genes were not detected.

CONCLUSION

Although the rates of antibiotic resistance among the isolates were high, the prevalence of carbapenemase producers was low. The finding of blaOXA-48 and blaNDM warrants upscaling of antimicrobial resistance surveillance programmes and fortification of infection prevention and control programmes in the country.

Whole Genome Sequencing Reveals Presence of High-Risk Global Clones of Klebsiella pneumoniae Harboring Multiple Antibiotic Resistance Genes in Multiple Plasmids in Mwanza, Tanzania

BACKGROUND

Klebsiella pneumoniae is an important multidrug-resistant (MDR) pathogen, causing both community- and healthcare-associated infections. The resistance is due to the continuous accumulation of multiple antibiotic-resistance-genes (ARGs) through spontaneous genomic mutations and the acquisition of conjugative plasmids. This study presents antibiotics resistance genes, plasmids replicons, and virulence genes of K. pneumoniae isolates from clinical specimens in a tertiary hospital, Mwanza, Tanzania.

METHODS

Whole genome sequencing (WGS) of 34 K. pneumoniae was performed, using an Illumina NextSeq 500, followed by in silco analysis.

RESULTS

A total of 34 extended-spectrum beta-lactamase-producing K. pneumoniae, isolated from blood samples from neonatal units were whole-genome sequenced. Of these, 28 (82.4%) had an identified sequence type (ST), with ST14 (39.3%, n = 11) being frequently identified. Moreover, 18 (52.9%) of the bacteria harbored at least one plasmid, from which a total of 25 plasmid replicons were identified with a predominance of IncFIB(K) 48.0% (n = 12). Out of 34 sequenced K. pneumoniae, 32 (94.1%) were harboring acquired antibiotic/biocides-resistance-genes (ARGs) with a predominance of bla_CTX-M-15 (90.6%), followed by oqxB (87.5%), oqxA (84.4%), bla_TEM-1B (84.4%) and sul2 (84.4%). Interestingly, we observed the ColRNAI plasmid-replicon (n = 1) and qacE gene (n = 4) for the first time in this setting.

CONCLUSION

Global high-risk clones of K. pneumoniae isolates carry multiple ARGs in multiple plasmid-replicons. Findings from this study warrant genomic-based surveillance to monitor high-risk global clones, epidemic plasmids and ARGs in low- and middle-income countries.

Identification and Characterization of Plasmids and Genes from Carbapenemase-Producing Klebsiella pneumoniae in Makkah Province, Saudi Arabia

Klebsiella pneumoniae (K. pneumoniae) is involved in several hospital and community-acquired infections. The prevalence of K. pneumoniae-producing-carbapenemase (KPC) resistance genes rapidly increases and threatens public health worldwide. This study aimed to assess the antibiotic resistance level of K. pneumoniae isolates from Makkah Province, Saudi Arabia, during the Islamic ‘Umrah’ ritual and to identify the plasmid types, presence of genes associated with carbapenem hydrolyzing enzymes, and virulence factors. The phenotypic and genotypic analyses based on the minimum inhibitory concentration (MIC), biofilm formation, PCR, and characterization of KPC-encoding plasmids based on the replicon typing technique (PBRT) were explored. The results showed that most isolates were resistant to carbapenem antibiotics and other antibiotics classes. This study identified sixteen different replicons of plasmids in the isolates and multiple genes encoding carbapenem factors, with blaVIM and blaOXA-48 being the most prevalent genes identified in the isolates. However, none of the isolates exhibited positivity for the KPC production activity. In addition, this study also identified six virulence-related genes, including kfu, wabG, uge, rmpA, fimH, and a capsular polysaccharide (CPS). Together, the data reported in this study indicate that the isolated K. pneumoniae during the pilgrimage in Makkah were all resistant to carbapenem antibiotics. Although the isolates lacked KPC production activity, they carried multiple carbapenem-resistant genes and virulence factors, which could drive their resistant phenotype. The need for specialized methods for KPC detection, monitoring the possibility of nosocomial transmission, and diverse therapeutic alternatives are necessary for controlling the spreading of KPC. This study can serve as a reference for clinicians and researchers on types of K. pneumoniae commonly found during religious gathering seasons in Saudi Arabia.

Antimicrobial resistance pattern, virulence determinants and molecular analysis of carbapenem-resistant Klebsiella pneumoniae isolated from clinical samples in Iran

Carbapenem-resistant Klebsiella pneumoniae (CRKP) has emerged as an important global threat in recent years. The objective of the present study was to characterize the molecular characteristics, antibiotic resistance pattern and the distribution of virulence factors in CRKP isolated from different clinical specimens. A total of 60 clinical CRKP isolates were collected from clinical samples. Based on Clinical Laboratory Standards Institute guidelines, antimicrobial susceptibility testing was assessed by the disk diffusion method. Carbapenem and aminoglycoside resistance determinants in addition to virulence genes were inspected by PCR. Molecular characteristics of CRKP isolates were analyzed by random amplified polymorphic DNA (RAPD) PCR and enterobacterial repetitive intergenic consensus (ERIC) PCR. All isolates were resistant to imipenem, meropenem, cefoxitin, levofloxacin, cefotaxime, ceftazidime and ciprofloxacin. Resistance to tetracycline, gentamicin and kanamycin were detected in 53%, 75% and 72% of isolates, respectively. The most common carbapenem resistance genes were OXA-48 (28.5%) and NDM (22%). The most common aminoglycosides resistance genes were aac6´Ib (57%) and aac(3)-IVa (28%). The most prevalent virulence genes were mrkD (82%), entB (62%) and ybts (58%). ERIC and RAPD analyses revealed 55 and 53 different patterns of CRKP isolates, respectively. We conclude that CRKP infections have been associated with different genotypes and that the carbapenemase type (OXA-48) and AME gene (aac6´-Ib) were widely distributed in CRKP isolates in our hospital. Continued compliance with existing phenotypes and genotypes, and strict enforcement of infection control guidelines, are recommended approaches for the prevention and dissemination of these strains.

Carbapenem-Resistant Klebsiella pneumoniae: Diversity, Virulence, and Antimicrobial Resistance

Background

Klebsiella pneumoniae (K. pneumoniae) is one of the most important pathogens in nosocomial infections. It has resistance to most antibiotics, even carbapenem, resulting in restricted therapeutic options.

Purpose

We tried to assess the antimicrobial resistance and virulence fitness of carbapenem-resistant K. pneumoniae (CRKP) in addition to their phenotypic and genotypic diversity.

Materials and Methods

The conventional methods, automated Vitek-32 system, and antimicrobial susceptibility pattern were used to detect CRKP isolates. Virulence and resistance genes profiles were created by using PCR technique. The correlation analysis was done by using R-program.

Results

The antimicrobial resistance profile for all our K. pneumoniae isolates was shocking as the MDR and CRKP were the most prominent phenotypes. Unfortunately, high degrees of heterogeneity among our CRKP isolates were recorded, as 97.5% of them were differentiated into different clusters. We found a negative correlation between the existence of virulence and antimicrobial resistance genes. In contrast to sputum and urine CRPK isolates, the blood isolates showed high antimicrobial resistance and low virulence fitness. Finally, K. pneumoniae creates several outbreaks and crises in Egypt owing to the highly heterogeneity and the wide spread of multidrug-resistant (MDR) and multi-virulent CRKP phenotypes.

Conclusion

Our results are significant and alarming to health organizations throughout the world for the severity and heterogeneity of K. pneumoniae infections. Therefore, the traditional method for treatment of CRKP infections must be renewed. Additionally, the treatment protocols must be well correlated with the site of infections, phenotypes, and genotypes of CRKP strains.

Molecular Detection of gyrA Mutation in Clinical Strains of Klebsiella pneumoniae

BACKGROUND

Multi-drug resistant (MDR) Klebsiella pneumoniae strains cause the majority of community acquired and life-threatening infections. We aimed to detect the gyrA mutations in the clinical strains of nalidixic acid and ciprofloxacin resistant K. pneumoniae isolated from the patients with urinary tract infections.

METHODS

Bacterial strains were isolated from the patients with urinary tract infections admitted to a major hospital in Tehran, Iran (2017-2018). Bacterial identification was done according to standard microbiological tests. Antimicrobial susceptibility testing for quinolones and fluoroquinolone antibiotics was done using both disc diffusion and minimal inhibitory concentrations (MICs) methods. PCR-RFLP was used to detect the probable mutation in the gyrA gene in nalidixic acid and ciprofloxacin resistant strains. Finally sequencing was performed to detect point mutations in isolated K. pneumoniae strains.

RESULTS

One hundred K. pneumonia isolates were recovered from the urine samples of the clinical cases. Antibiotic resistance testing showed that among all K. pneumoniae isolates, 26% and 19% of the strains were resistant to nalidixic acid and ciprofloxacin respectively. MIC value was ≥4 μg/ml for ciprofloxacin resistant isolates. The results of RFLP on gyrA PCR amplicons using HinfI restriction enzyme showed point mutation in this gene in 46% of nalidixic acid and ciprofloxacin resistant K. pneumonia. The data obtained from the sequencing confirmed the RFLP results and indicated the presence of point mutations in codons 83 and 87 in the gyrA gene which leads to the substitution of different amino acids in gyrA protein.

CONCLUSION

Our findings indicated a relative increased rate of resistance against quinolones and fluoroquinolone antibiotics that raised a concern about extensive dissemination of clinical strains of nalidixic acid and ciprofloxacin resistant K. pneumonia. Point mutation of gyrA gene was responsible for the resistance in our strains however to gain more insight into the molecular characterization of quinolone-resistant isolates, other possible mechanisms of the resistance should also be investigated.

Phenotypic and genotypic detection of extended spectrum beta lactamase enzyme in Klebsiella pneumoniae

BACKGROUND

Klebsiella species are ubiquitous in nature and can be found in the natural environment and on mucosal surfaces of mammals and it is an important multidrug-resistant pathogen affecting humans and is a major source for hospital acquired infections. The aim of this study is to investigate the prevalence of ESBL enzyme among Klebsiella pneumoniae isolates by phenotypic methods from different hospital wards and detection of ESBL resistance genes such as TEM and SHV in Sulaimani city/ Kurdistan-Iraq.

METHODS

Klebsiella pneumoniae isolates were collected from different clinical samples from different hospitals, the isolates were identified by standard technique. Screening of ESBLs was undertaken by using double disk diffusion and standard disk diffusion methods. Real-time PCR was used for genotypic detection of TEM and SHV genes according to the standard protocol.

RESULT

Out of 54 Klebsiella pneumoniae isolates; 28 were ESBL positive, The pattern of antimicrobial susceptibility testing showed that the most resistant antibiotic are AMP (100%), AMC (100%) followed by CAZ (83.33%), CTX (75.9%), CPM (74%), ATM (70.37%). Both TEM and SHV genes were detected among 28 (51.85%) ESBL positive by using Real-time PCR method.

CONCLUSION

SHV gene was detected in most of the isolates of ESBL producers of Klebsiella pneumoniae.

Antimicrobial Resistance Genes, Virulence Genes, and Associated Mobile Genetic Elements of Eight Multidrug-Resistant Enterobacterales Isolated from Hospital-Acquired Urinary Tract Infections in Sri Lanka

The study describes the first isolation of multidrug-resistant (MDR) Klebsiella pneumoniae ST16, Escherichia coli ST131 (Esc), and Enterobacter hormaechei subsp. steigerwaltii ST93 (Enterobacter cloacae complex [ECC]) in Sri Lanka. Eight MDR strains of uropathogenic Enterobacterales isolated from hospital acquired urinary tract infections (UTIs) were analyzed using genomic sequencing and comparative genomics. Isolates carried multiple carbapenemase, AmpC, and ESBL (extended-spectrum β-lactamase) genes. ECC manifested both bla_NDM-4 and bla_OXA-181. The K. pneumoniae strains harbored fimbrial genes that facilitate pathogenesis of UTI. Several extraintestinal pathogenic E. coli associated virulence genes were identified in Esc. The efflux pump gene, acrA, and the T6SS gene cluster were detected in ECC. Many antimicrobial resistance (AMR) and virulence genes were identified associated with mobile genetic elements. ISEcp1 flanked upstream of bla_CTX-M-15. The carbapenemase genes were carried on ColKP3 plasmids and were associated with ISEcp1. In Esc, the AMR gene bla_TEM-1B and virulence gene traT were found on an IncF plasmid replicon. In K. pneumoniae the AMR genes sul1 and tetB present on IncR plasmid replicons and were associated with the insertion sequence IS6100. In Kp5, bla_LAP-2 and qnrS1 coexisted and were flanked by ISEcl. AMR gene clusters, conferring resistance to multiple antimicrobial classes, flanked by mobile elements were identified in seven isolates.

Molecular Characterization of Antibiotic Resistance and Genetic Diversity of Klebsiella pneumoniae Strains

The aims of this study were the molecular characterization of antibiotic resistance and genotyping of Klebsiella pneumoniae strains isolated from clinical cases in Tehran, Iran. A total of 100 different types of clinical human samples were collected from a major teaching hospital in Tehran, Iran. Bacterial isolates were identified using standard microbiological tests. Antimicrobial susceptibility testing was done according to the latest CLSI guidelines. PCR was used to amplify the gyrA gene in quinolone-resistant isolates and sequencing was performed for the detection of probable mutations between the isolates. The occurrence of plasmid-mediated quinolone resistance genes (qnrA, qnrB, and qnrS) was also investigated by PCR. Finally, genotyping of the strains was performed by PFGE in a standard condition. The susceptibility pattern revealed a high and low level of resistance against meropenem (20%) and trimethoprim (37%), respectively. PCR and sequencing detected mutation in the gyrA gene in 51% of quinolone-resistant K. pneumoniae. According to the susceptibility report, among nalidixic acid-resistant strains, 60.5%, 50%, and 42.9% of isolates contained qnrA, qnrB, and qnrS, respectively. Among ciprofloxacin-resistant strains, qnrA was the most frequent PMQR gene. The PFGE differentiated the strains into 31 different genetic clusters so that the highest number (7/66) was in category A. Our results indicated that the frequency of resistance to various antibiotics particularly trimethoprim, nalidixic acid, and cefoxitin are increasing. The presence of qnr (S and A) genes and point mutation of the gyrA gene were likely to be responsible for the resistance toward nalidixic acid and ciprofloxacin in our strains. Also, the results obtained from genotyping indicated that the K. pneumoniae strains isolated in this study belonged to the diverse clones.

Detection of blaKPC and blaNDM carbapenemase genes among Klebsiella pneumoniae isolates in Addis Ababa, Ethiopia: Dominance of blaNDM

Background

Infections caused by Klebsiella pneumoniae have been difficult to control because of the worldwide emergence of carbapenem-resistant isolates mainly due to carbapenemase production. Information regarding carbapenemase-producing K. pneumoniae is still scarce in Ethiopia. Therefore, the current study aimed to determine the prevalence of carbapenemase-producing K. pneumoniae and to assess the occurrence of bla_NDM and bla_KPC carbapenemase genes_.

Methods

A cross-sectional study was conducted from September 2018 to February 2019 at Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia. A total of 132 non-duplicate K. pneumoniae isolates were studied. Phenotypic confirmation of carbapenemase production was done by modified Carbapenem Inactivation Method (mCIM). Multiplex PCR was performed for the detection of carbapenemase-encoding genes bla_KPC, and bla_NDM.

Results

Out of the total 132 K. pneumoniae isolates, 39 (29.6%) were non-susceptible to one or more carbapenems. The prevalence of carbapenemase-producing isolates from the total was 28 (21.2%) with mCIM of which the most dominant gene was bla_NDM 26 (92.9%) and one isolate carried bla_KPC concomitantly. Carbapenemase-producing K. pneumoniae isolates were 100% non-susceptible to half of the antimicrobials used in the study, including meropenem and ertapenem. Previous use of carbapenems was associated with carbapenemase production (P = 0.004).

Conclusions

The prevalence of carbapenemase-producing K. pneumoniae isolates was worrying in the study area. To our knowledge, the study described the emergence of bla_NDM and bla_KPC gene carrying K. pneumoniae in Ethiopia for the first time. Further large-scale molecular-based studies, including other carbapenemase genes and sequencing of K. pneumoniae, are warranted to have a clear awareness about the presence of antimicrobial resistance high-risk clones in Ethiopia.

Biotyping, Virulotyping and Biofilm Formation Ability of ESBL-Klebsiella pneumoniae Isolates from Nosocomial Infections

The aim of this study was to investigate the frequency, molecular characterization, virulence genes, resistance genes and antimicrobial profile of nosocomial extended spectrum beta lactamase producing Klebsiella species. A total of 22 (12.2%) K. pneumoniae strains were isolated from 180 clinical samples collected from hospitalized patients in Egypt. K. pneumoniae biotypes were B1 (72.8%), B3 (13.6%) and B4 (13.6%). The isolates were classified for the capsular serotypes, 86.4% (20/22) were of K1 serotype, while only two isolates (13.64%) were of K2 serotype. Hypermucoviscous K. pneumoniae isolates accounted for 68.2%. Biofilm formation ability of K. pneumoniae was determined by microtitre plate method. The majority of the isolates (40.9%) were moderate biofilm producers, while 27.3% were strong biofilm producers. All K. pneumoniae strains were positive for fimH and traT genes, while magA was identified in only 63.6% of the isolates. The antibiotic susceptibility profile of the isolates (n=22) was determined by the disc diffusion technique using 23 different antibiotics. Streptomycin and imipenem are the most effective antibiotics against 22 tested K. pneumoniae isolates with sensitivity rates of 63.64% and 54.54%, respectively. All tested K. pneumoniae isolates showed high resistance to amoxicillin∕clavulanate (100%), cefuroxime (100%) and ceftazidime (95.45%). Extended spectrum beta lactamases (ESBL) production and the presence of ESBL related genes were tested in the isolates. All the isolates tested positive for blaVIM, NDM1, and blaTEM, while only 81.8 percent tested positive for the blaSHV gene. Increasing antimicrobial resistance in K. pneumoniae causing nosocomial infections limits the use of antimicrobial agents for treatment. Furthermore, the spread of biofilm, multiple drug resistant and ESBL-producing K. pneumoniae isolates is a public threat for hospitalized patients.

Characterization of virulence factors and antibacterial activity of curcumin in hypervirulent Klebsiella pneumoniae

Aim: Klebsiella pneumoniae is a threat to human health due to its carbapenem-resistance and hypervirulent phenotype. Curcumin is a well-known antimicrobial agent. Hence, it is important to investigate the antivirulence activity of curcumin against hypervirulent K. pneumoniae isolates. Materials & methods: Carbapenemase presence and prevalence of hypervirulent isolates were determined. Inhibition of biofilm formation and expression of virulence genes were analyzed by colorimetry and real-time PCR tests. Results: Sixteen hypervirulent K. pneumoniae isolates were identified. The optimum activity of curcumin was detected at 1/2 minimum inhibitory concentration. Curcumin possessed appropriate antibiofilm, anti-efflux and anticapsule activities. Conclusion: According to the crucial role of biofilm, capsule and efflux systems in the pathogenesis of hypervirulent K. pneumoniae, curcumin may be used to improve anti-Klebsiella treatment.

An in Vitro Study of Molecular Effects of a Combination Treatment with Antibiotics and Nanofluid Containing Carbon Nano-tubes on Klebsiella pneumoniae

Background:

We aimed to prepare a nanofluid, containing f-MWCNTs, and investigate the antibacterial efficacy of f-MWCNTs+ ciprofloxacin (cip) on Klebsiella pneumoniae by evaluating the virulence gene expression.

Methods:

This study was carried out from 2019 to 2020, in the Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran. The nanofluid containing antibiotic and f-MWCNTs were prepared by the ultrasonic method. The minimum inhibitory concentrations (MICs) of ciprofloxacin and f-MWCNTs were determined using the broth micro dilution MIC tests. For examining the antibacterial effects, the expression level of virulence genes, under the influence of f-MWCNTs, was evaluated by a real-time PCR.

Results:

The effect of 8 μg/ml ciprofloxacin + 400 μg/ml f-MWCNTs, completely inhibited the growth of the resistant isolate of K. pneumoniae, while, in the ATCC 700,603 isolate, 2 μg/ml ciprofloxacin with 100 μg/ml f-MWCNT could inhibit a bacterial growth. In the resistant K. pneumoniae clinical isolate, after f-MWCNT+cip treatment, the expression of fimA, fimD, wza, and wzi genes was significantly downregulated, compared to the ciprofloxacin treatment, and upregulated, compared to the negative control. For the ATCC 700,603 isolate treated with f-MWCNT+cip, the expression of fimA, fimD and wza virulence genes showed upregulation, compared to the negative control and downregulated in comparison with the ciprofloxacin treatment.

Conclusion:

Simultaneous treatment of resistant isolate of K. pneumoniae with f-MWCNTs +antibiotic could improve the effectiveness of antibiotic at lower doses, due to the reduced expression of virulence genes in comparison with antibiotic treatment, besides the increased cell wall permeability to antibiotics.

Klebsiella-induced infections in domestic species: a case-series study in 697 animals (1997-2019)

Klebsiella species, particularly K. pneumoniae, are well-known opportunistic enterobacteria related to complexity of clinical infections in humans and animals, commonly refractory to conventional therapy. The domestic animals may represent a source of the pathogenic and multidrug-resistant Klebsiella species to humans. Nevertheless, most studies involving Klebsiella-induced infections in domestic animals are restricted to case reports or outbreaks. We retrospectively investigated selected epidemiological data, clinical aspects, and in vitro susceptibility pattern of 697 non-repetitive Klebsiella infections in livestock and companion species (1997-2019). The isolates were obtained from different clinical disorders from dogs (n = 393), cattle (n = 149), horses (n = 98), cats (n = 27), pigs (n = 22), sheep (n = 5), goats (n = 2), and buffalo (n = 1), except four isolates from subclinical bovine mastitis. Urinary (223/697 = 32%), enteric (117/697 = 16.8%), mammary (85/697 = 12.2%), reproductive (85/697 = 12.2%), and respiratory disorders (67/697 = 9.6%) were the most common clinical manifestations. Other miscellaneous clinical pictures (116/697 = 16.6%) included abscesses, otitis, hepatitis, conjunctivitis, pyodermitis, sepsis, and encephalitis. Norfloxacin (183/245 = 74.7%) and gentamicin (226/330 = 68.5%) were the most effective antimicrobials. High in vitro resistance of the isolates was seen to ampicillin (326/355 = 91.8%), amoxicillin/clavulanic acid (25/62 = 40.3%), and trimethoprim/sulfamethoxazole (100/252 = 39.7), and multidrug resistance to ≥ 3 classes of antimicrobials was found in 20.4% (142/697) isolates. Wide variety of clinical manifestations of Klebsiella-induced infections was observed, with a predominance of urinary, enteric, mammary, reproductive, and respiratory tract disorders, reinforcing opportunistic behavior of agent. Poor in vitro efficacy was observed to some conventional antimicrobials and ~ 20% of isolates exhibited resistance pattern, reinforcing the need for proper use of drugs on therapy approaches in domestic animals to avoid multidrug-resistant bacteria, an emergent global concern.

Studies on molecular epidemiology of ESβL-producing Klebsiella pneumoniae isolated from patients hospitalized in a specialist hospital in southern Poland

Introduction. Extended-spectrum β-lactamase (ESβL)-producing Klebsiella pneumoniae is currently one of the most common causes of nosocomial infections worldwide. The study aimed to characterize antibiotic resistance profile, the prevalence of selected genes encoding ESβLs, virulence, and the genetic relationship in 139 K. pneumoniae isolates identified in John Paul II Specialist Hospital in Southern Poland, collected in 2016.

Materials/Methods. Bacterial identification and the preliminary antibiotic susceptibilities was performed using the VI-TEK® 2 Compact automated system. Genes encoding ESβLs were amplified by CTX-Mplex PCR and PCR reactions. The presence of nine genes encoding virulence factors was studied by multiplex PCR. Clonality was investigated by PFGE after digestion with SpeI endonuclease.

Results. K. pneumoniae were mostly recovered from the respiratory tract (40.3%), urine (32.4%), wound swabs (19.4%) and blood (5%). In summary, 82.7% of strains were classified as multidrug resistant (MDR). All isolates were confirmed as ESβL producers and carried bla CTX-M-type (85.6%), bla SHV (82%), bla TEM (77.7%), bla CTX-M-9 (75.6%) and bla CTX-M-1 (1.4%) in various combinations. Moreover, triple bla genes were observed in 72% of isolates. The most common virulence-as-sociated genes found among the isolates were entB (91.4%), ybtS (55.4%), iutA (55.4%), magA (53.2%), kfu (14.4%), K2 (11.5%), mrkD (10.1%), rmpA (7.9%) and allS (5%). The PFGE analysis identified 4 major clusters (A–D) comprising 61% of the entire collection.

Conclusions. Our results indicate that the presence of a wide variety of MDR K. pneumoniae harbor ESβLs and virulence genes. Studies on molecular epidemiology of ESβL-producing K. pneumoniae isolates are needed, particularly for epidemiological surveillance in the hospital environment.

The Association of the Phylogenetic Typing of the Klebsiella pneumoniae Isolates with Antibiotic Resistance

Klebsiella pneumoniae complex (KPC) accounts for approximately one-third of all Gram-negative infections. Moreover, it is highly resistant and can taxonomically be distributed into KpI, KpII, and KpIII phylogroups. This study aimed to investigate the distribution of phylogenetic groups and the relationship between them and antibiotic resistance patterns. For this purpose, we collected KPC isolates from Tabriz, Iran, between 2018 and 2020. Antimicrobial susceptibility testing was performed by disk diffusion agar, and phylogenetic groups were then examined using gyrA restriction fragment length polymorphism (RFLP) and parC PCR methods. A total of 100 KPC isolates were obtained from the clinical specimens (urine, respiratory secretion, blood, wounds, and trachea). The enrolled patients included 47 men and 53 women aged from 1 to 91 years old. The highest sensitivity was found related to fosfomycin as 85%, followed by amikacin as 66%. The three phylogenetically groups by the RFLP-PCR method were found in KPC, 96% (96 isolates) as KpI, 3% (3 isolates) as KpII, and 1% (1isolate) as KpIII. The highest antibiotic resistance was observed in KpI. It was shown that a valid identification of three phylogenetic groups of KPC can be done by combining both gyrA PCR-RFLP and parC PCR. Of note, the KpI group was also observed as the dominant phylogenetic group with the highest resistance to antibiotics.

Virulence factors, antibiotic resistance patterns, and molecular types of clinical isolates of Klebsiella Pneumoniae

BACKGROUND

Klebsiella pneumoniae is armed with a wide range of antibiotic resistance mechanisms that mostly challenge effective treatment. The aims of the current study were to identify the clinical strains of K. pneumoniaealso to determine their phenotypes and molecular characterization related to antimicrobial resistance and virulence genes.

RESEARCH DESIGN AND METHODS

In this investigation, clinical specimens from different hospitals located in Tehran, Iran, were collected during a nine-month period (December 2018 to August 2019). The K. pneumoniae strains were isolated and identified through standard microbial and biochemical assays. Additionally, disk diffusion, combined disk, Modified Hodge Test (MHT) and PCR were performed for antibiotic resistance and virulence gene analysis, respectively.

RESULTS

Eighty-four isolates of K. pneumoniae were subjected to the study. According to the combined disk and modified Hodge test results, 27 (52%) and 15 pathotypes (62.5%) out of resistant strains of isolated K. pneumoniae were detected as ESBL and KPC producers. The virulence genes of mrkD (94%) and magA (11%) were the highest and lowest among isolates, respectively.

CONCLUSIONS

The high prevalence of antibiotic resistance and virulence genes in conjunction with a significant relationship between the strains revealed a high pathogenic capacity of the isolated pathotypes of K. pneumoniae.

Detection of carbapenemase-producing, hypervirulent Klebsiella spp. in wastewater and their potential transmission to river water and WWTP employees

Wastewater treatment plants (WWTPs) release drug-resistant microorganisms to water bodies (with effluents), and WWTP employees are exposed to bioaerosol emissions from the processed wastewater. Bacteria of the genus Klebsiella, in particular carbapenemase-producing (CP), hyper-virulent (Hvr) strains of Klebsiella pneumoniae, play a special role in this process. Klebsiella spp. strains isolated from wastewater, river water and the upper respiratory tract of WWTP employees were analyzed in this study. The isolated strains were identified as K. pneumoniae (K. pn) or K. non-pneumoniae (K. npn). The prevalence of nine types of genes encoding resistance to beta-lactams, nine genes encoding virulence factors and K1/K2 capsular serotypes, three genes encoding multi drug effluent pump systems, and the class 1 integron-integrase gene was determined by PCR. A total of 284 Klebsiella spp. isolates were obtained in the study: 270 environmental strains and 14 strains from the upper respiratory tract. Among environmental isolates 90.7% (245/270) harbored beta-lactam resistance genes, 17.4% (47/270) were classified as CP strains, 11.1% (30/270) were classified as Hvr strains, and 1.9% (5/270) were classified as CP-Hvr strains. CP-Hvr strains were also isolated from WWTP employees. Genes encoding β-lactamases (including carbapenemases), complete efflux pump systems and the K1 serotype were identified more frequently in K. pn strains. In turn, K. npn strains were characterized by a higher prevalence of bla_SHV and intI1 genes and K2 serotype gene. The strains isolated from wastewater and river water also differed in the abundance of drug resistance and virulence genes. The results of the study indicate that CP-Hvr K. pn strains are possibly transmitted from wastewater via bioareosol to the upper respiratory tract of WWTP employees. bla_GES-type carbapenemases significantly contributed to the spread of drug resistance in the environment.

Antibiotic resistance, virulence-associated genes analysis and molecular typing of Klebsiella pneumoniae strains recovered from clinical samples

Klebsiella pneumoniae is a multidrug-resistant (MDR) opportunistic pathogen that causes nosocomial infections. Virulence analysis and molecular typing as powerful approaches can provide relevant information on K. pneumoniae infection. In the current study, antibiotic resistance, virulence-associated genes analysis, as well as molecular typing of K. pneumoniae strains were investigated. Out of 505 clinical samples collected from hospitalized patients, 100 K. pneumoniae strains were isolated by standard microbiological methods and subjected to the phenotypic and genotyping analysis. The highest prevalence of resistance was observed against ciprofloxacin (75%), trimethoprim-sulfamethoxazole (73%) and nitrofurantoin (68%). Virulence associated genes including entB, traT, ybts, magA, iucC, htrA and rmpA were found in 80%, 62%, 75%, 5%, 30%, 72% and 48%, of the isolates, respectively. The prevalence of biofilm-associated genes including mrkA, fimH, and mrkD were equally 88% for all tested isolates. Moreover, the efflux pump genes including AcrAB, TolC and mdtK were observed in 41 (41%), 33 (33%) and 26 (26%) of the strains respectively. A significant statistical association was observed between MDR strains and high expression of efflux pump and biofilm genes. The K. pneumoniae strains were differentiated into 11 different genetic patterns using the repetitive element sequence-based PCR (rep-PCR) technique. High prevalence of resistance, presence of various virulence factors, high level of efflux pump, and biofilm gene expression in diverse clones of K. pneumoniae strains pose an important health issue in clinical settings.

Klebsiella pneumoniae pneumonia in patients with rheumatic autoimmune diseases: clinical characteristics, antimicrobial resistance and factors associated with extended-spectrum β-lactamase production

Background

Over the past decades, Klebsiella pneumoniae (K. pneumoniae) infections have been increasing and affected immunocompromised patients nosocomially and communally, with extended-spectrum β-lactamase (ESBL) production becoming a major concern. Patients with rheumatic autoimmune diseases, mostly receiving immunosuppressive therapy, are vulnerable to various infections, including K. pneumoniae. However, few have investigated K. pneumoniae infections in this specific population. This study aimed to identify factors associated with ESBL production and mortality of K. pneumoniae pneumonia among patients with rheumatic autoimmune diseases in the Emergency Department.

Methods

We retrospectively investigated patients with rheumatic diseases who were diagnosed with K. pneumoniae pneumonia. The diagnosis of K. pneumoniae pneumonia was based on clinical manifestations, radiological findings and microbiological testing results. Prognostic factors and risk factors for ESBL production were determined with univariate and multivariate logistic regression analysis. Empirical therapy and antimicrobial susceptibility data were also collected.

Results

Of 477 K. pneumoniae pneumonia patients, 60 were enrolled into this study. The in-hospital mortality was 28.3%. Septic shock, ICU admission, the need for mechanical ventilation and change of antibiotics due to clinical deterioration, all related to mortality, were included as unfavorable clinical outcomes. Multivariate analysis suggested that ESBL production (OR, 6.793; p = 0.012), initial PCT ≥ 0.5 ng/ml (OR, 5.024; p = 0.033) and respiratory failure at admission (OR, 4.401; p = 0.046) predicted increased mortality. ESBL production was significantly associated with dose of corticosteroids (OR, 1.033; p = 0.008) and CMV viremia (OR, 4.836; p = 0.032) in patients with rheumatic autoimmune diseases. Abnormal leukocyte count (OR, 0.192; p = 0.036) was identified as a protective factor of ESBL-producing K. pneumoniae pneumonia. The most commonly used empirical antibiotic was ceftazidime, while most isolates showed less resistance to carbapenems and amikacin in susceptibility testing.

Conclusions

K. pneumoniae pneumonia could be life-threatening in patients with rheumatic autoimmune diseases. Our findings suggested that ESBL production, initial PCT ≥ 0.5 ng/ml and respiratory failure at admission were independent factors associated with poor prognosis. Dose of corticosteroids and CMV viremia, predicting ESBL production in K. pneumoniae pneumonia, may help make individualized antibiotic decisions in clinical practice.

The Emergence of Klebsiella pneumoniae with Reduced Susceptibility Against Third Generation Cephalosporins and Carbapenems in Lagos Hospitals, Nigeria

This study investigated the prevalence of Klebsiella (K.) pneumoniae isolates among clinical samples of patients in four medical centers in Lagos, Nigeria and the burden of extended-spectrum beta-lactamases (ESBL) and carbapenem-resistant K. pneumoniae (CRKP) strains. Different samples (stool, blood, urine, wound swabs and nasal swabs) from 127 patients with suspected Gram-negative infections based on on-site performed Gram-stain from four public hospitals between March and September 2015 were analyzed. K. pneumoniae was identified in 43 (34%) patients. Resistance rates of these 43 strains according to the CLSI breakpoints were as followed: cotrimoxazole (90.7%), cefuroxime (74.4%), ofloxacin (55.8%), ceftazidime (46.5%), and cefixime (35%). Three isolates (7%) were resistant to imipenem. All isolates were susceptible to amoxicillin/clavulanic acid and nitrofurantoin. The prevalence of ESBL-producing, MDR and CRKP strains was 69.8%, 62.8%, and 7.0%, respectively. Of the ESBL-producing isolates, two K. pneumoniae isolates obtained from urine harbored both bla_SHV and bla_CTX-M-1, and a third isolate from urine harbored only the bla_CTX-M-1. This study revealed the emergence of CRKP isolates and bla_CTX-M-1 and bla_SHV co-harboring K. pneumoniae strains in Lagos hospitals. The emergence of CRKP strains is an early warning signal for carbapenem antibiotics’ prudent use with concern for their efficacies.

Molecular insights of Carbapenem resistance Klebsiella pneumoniae isolates with focus on multidrug resistance from clinical samples

BACKGROUND

Carbapenem are the last-line antibiotic, defence against Gram-negative extended spectrum ß-lactamases producers (ESBLs). Carbapenem resistance Enterobacteriaceae especially Carbapenem resistant-Klebsiella pneumoniae (CR-KP) is recognized as one of the well-known public health problem, which is increasingly being reported around the world. The present study was focused to analyse the prevalence and characterization of antibiotic resistance K. pneumoniae in centre region of Tamil Nadu, India.

METHODOLOGY

Totally 145 suspected K. pneumoniae isolates [Urine, Pus, Sputum, Blood and Biopsy] obtained from hospitals of Central South India. The isolates were subjected to biochemical and molecular identification technique, following with antibiotic resistance pattern by standard antibiotic sensitivity test. Multidrug resistance (MDR) with β-lactamase producing Carbapenem resistant K. pneumoniae (CR-KP) strains were screened by classical sensitivity method and also drug resistance encoded gene. Also, molecular typing of the MDR strains were characterized by Pulsed-Field Gel Electrophoresis (PFGE). Further, the outer membrane protein (OmpK35 and 36) related Carbapenem resistance were characterized.

RESULTS

Totally, 61% of isolates were confirmed as K. pneumoniae, 75 % of isolates were MDR including 58% carbapenem and 97% ESBL antibiotics and grouped into 17 distinct resistant patterns. The MDR KP isolates shows positive for blaCTXM-1 (92 %) gene followed by blaSHV (43 %), blaTEM (36 %), blaNDM-1 (26 %), blaGES (20 %) and blaIMP-1 (8 %). Moreover, 62 % CR-KP isolates loses OmpK36 and 33% isolates loses OmpK35.

CONCLUSIONS

Loss of OmpK36 were highly an influence the cefoxitin and carbapenem resistance. Sixteen different PFGE patterns have been observed among the 18 MDR isolates. Eventually, ESBL as well as CR-KP were diverse in genetic makeup and often associated with hyper virulence hvKP should be of serious concern.

Evaluation of Resistance Mechanisms in Carbapenem-Resistant Enterobacteriaceae

BACKGROUND

Carbapenem-resistant Enterobacteriaceae (CRE) is a major concern leading to morbidity and mortality in the world. CRE often is becoming a cause of therapeutic failure in both hospital and community-acquired infections.

AIM

This study aimed to investigate the resistance mechanisms of CRE by phenotypic and molecular methods.

MATERIALS AND METHODS

Sixty CRE (50 Klebsiella pneumoniae, 6 Escherichia coli, and 4 Enterobacter spp.) were isolated from October 2018 to June 2019. Antimicrobial susceptibility testing was carried out using phenotypic methods. The carbapenem resistance mechanisms including efflux pump hyperexpression, AmpC overproduction, carbapenemase genes, and deficiency in OmpK35 and OmpK36 were determined by phenotypic and molecular methods, respectively.

RESULTS

Sixty CRE (50 Klebsiella pneumoniae, 6 Escherichia coli, and 4 Enterobacter spp.) were isolated from October 2018 to June 2019. Amikacin was found to be the most effective drug against CRE isolates. All isolates were resistant to imipenem and meropenem by the micro-broth dilution. AmpC overproduction was observed in all Enterobacter spp. and three K. pneumoniae isolates. No efflux pump activity was found. Carba NP test and Modified Hodge Test could find carbapenemase in 59 (98%) isolates and 57 (95%) isolates, respectively. The most common carbapenemase gene was bla OXA-48-like (72.8%) followed by bla NDM (50.8%), bla IMP (18.6%), bla VIM (11.8%), and bla KPC (6.7%). The ompK35 and ompK36 genes were not detected in 10 and 7 K. pneumoniae isolates, respectively.

CONCLUSION

The amikacin is considered as a very efficient antibiotic for the treatment of CRE isolates in our region. Carbapenemase production and overproduction of AmpC are the main carbapenem resistance mechanisms in CRE isolates. Finally, Carba NP test is a rapid and reliable test for early detection of carbapenemase-producing isolates.

Virulence characterization of Klebsiella pneumoniae and its relation with ESBL and AmpC beta-lactamase associated resistance

BACKGROUND AND OBJECTIVES

Trend analysis reveals that Klebsiella pneumoniae has witnessed a steep enhancement in the antibiotic resistance and virulence over the last few decades. The present investigation aimed at a comprehensive approach investigating antibiotic susceptibility including, extended spectrum beta-lactamase (ESBL) and AmpC β-lactamase (AmpC) resistance and the prevalence of virulence genes among the K. pneumoniae isolates.

MATERIALS AND METHODS

Sixty-one K. pneumoniae isolates were obtained from various clinical infections. Antimicrobial susceptibility was performed by disk diffusion method. The Mast® D68C test detected the presence of ESBLs and AmpCs phenotypically, and later presence of ESBL and AmpC genes was observed by polymerase chain reaction (PCR). Multiplex-PCR was performed to investigate various virulence genes.

RESULTS

Amongst 61 K. pneumoniae isolates, 59% were observed as ESBL and 14.7% as AmpC producers. All ESBL producers were positive for bla _CTX-M-15 , while bla _CTX-M-14 was observed in 54.1% isolates. The frequency of AmpC genes was as follows: bla _CMY-2 (60.7%) and bla _DHA-1 (34.4%). The most frequent virulence genes were those encoding enterobactin and lipopolysaccharide. Presence of mrkD was associated with bla _DHA-1 gene, while bla _CMY-2 significantly (p≤0.05) correlated with the presence of iutA and rmpA virulence genes. bla _DHA-1 positive isolates had urine as a significant source, while bla _CMY-2 positive isolates were mainly collected from wound exudates (p≤0.05).

CONCLUSION

Our results highlight that ESBL and AmpC production along with a plethora of virulence trait on K. pneumoniae should be adequately considered to assess its pathogenesis and antibiotic resistance.