Pneumonia Strains Research Articles

Relationship Between Drug Resistance Characteristics and Biofilm Formation in Klebsiella Pneumoniae Strains.

To conduct epidemiological analysis of Klebsiella pneumoniae (K. pneumoniae) with hypervirulence, and to investigate its drug resistance phenotype, Extended-spectrum β-lactamase (ESBLs) gene, virulence factor, capsular serotype and biofilm formation, so as to provide theoretical basis for further understanding of the drug resistance mechanism of K. pneumoniae with hypervirulence. K. Pneumoniae were isolated from clinical samples collected from inpatients. All strains were identified by VITEK2 Compact using fully automatic microbial analyzer, the minimal inhibitory concentration (MIC) of antibiotics was determined by microbroth dilution test. The double disk diffusion method was used to detect the production of ESBLs, modified carbapenem inactivation method (mCIM) was used to detect the production of carbapenemase, and hypermucoviscosity phenotype was detected by wire drawing test. PCR was used to detect ESBLs gene, virulence factor and capsular serotype. Crystal violet staining was used to detect the ability of biofilm formation. The ESBLs genes detected in this study included strains blaTEM 35 (36.5%), blaSHV 51 (53.1%), and blaCTX-M 49 (51.0%). Most strains carried multiple ESBLs genes, but not all of them produce ESBLs. K1 and K2 accounted for 14.6% and 11.5% respectively. Most (91.7%) strains carried the fimH gene, and the other virulence genes were ybtS (53.1%), entB (46.9%), rmpA (41.7%), aerobactin (32.3%), allS (15.6%), kfu (15.6%). Of all the Klebsiella pneumoniae strains, 33 (34.4%) exhibited ESBLs phenotype, 16 (16.7%) were carbapenemase-producing, and 20 (20.8%) with ESBLs phenotype tested were resistant to all four drugs. The correlation between ESBLs-producing strains and biofilm formation was significantly increased compared to strains without ESBLs phenotype (P=0.035). Compared to hypervirulent Klebsiella pneumoniae (hvKP), classical Klebsiella pneumoniae (cKP) has a tendency to acquire antibiotic resistance. Our study showed that genes encoding rmpA, K1 or K2, and kfu were highly associated with hvKP.

Оценка литической активности бактериофагов в отношении Klebsiella pneumoniae, выделенных у детей с пневмококковым носительством

Streptococcus pneumoniae and Klebsiella pneumoniae are opportunistic pathogens, commensals; at the same time, they can cause life-threatening infections. These bacteria have a plastic genome and can evade the host’s immune response. Antibiotic-resistant strains are of particular concern. The use of bacteriophages is considered as an alternative or adjunct to antimicrobial therapy. Sensitivity to antimicrobial drugs and to bacteriophages of 70 strains of Klebsiella pneumonia was studied, which were isolated from Streptococcus pneumoniae carriers who applied for diagnostic research in consultation and diagnostic polyclinic of Kazan Scientific Research Institute of Epidemiology and Microbiology of Rospotrebnadzor. Based on the results of phagolysability of K. pneumoniae isolates with different sensitivity profiles to antimicrobial drugs, phage preparations were ranked in the following sequence (as activity decreases): Klebsiella bacteriophage polyvalent purified > Pyobacteriophage complex > sextaphage.

Facile construction of antibiotics-loaded glucose-capped gold nanoparticles for in vitro antimicrobial and treatment and care of severe Pneumonia

From the perspective of gold nanoparticles (GNPs)′ potential antibacterial applications, we demonstrate the fabrication, characterization, and effective antimicrobial activity of gentamicin (GM) and kanamycin (KAN) dynamically loaded to glucose-capped gold nanoparticles (g-GNPs). Infra-red (FT-IR) spectroscopy analyzed the synthesized GNPs and g-GNPs with encapsulated antibiotic drugs. Various spectroscopical methods characterized g-GNPs and drug-loaded nanoparticles. A minimum inhibitory concentration (MIC) and active curves in the Klebsiella pneumonia strain were used to evaluate the antibacterial activity of aminoglycoside-loaded g-GNPs, and the results showed that the nanoparticles had an appropriate antimicrobial effect on the clinical strain of the bacteria. There were bacteriostatic effects and an inhibiting effect on the growth of bacteria at doses of 33 to 65 μg ml−1 for each GM@g-GNPs and KAN@g-GNPs. With zones of Inhibition (ZOI) of 27 and 29 mm, g-GNPs-loaded antimicrobial medications demonstrated more antibacterial activity in well diffusion experiments than free nanomaterials and antimicrobial drugs, with ZOI of 21.00 and 10.00 mm, respectively. GM and KAN-loaded g-GNPs were examined using crystal violet assay for their antibiofilm activity. Findings suggested that the concentration of nanoparticles and anti-biofilm activity were directly linked. The cell membrane integrity was assessed in g-GNPs loaded with GM and KAN, and the results showed that nucleic acids and proteins released into the environment were significant. The inhibitory effects of GM@g-GNPs and KAN@g-GNPs on bacterial efflux pump (EP) was assessed, and the result displayed that all strains were sensitive to moderate concentration of NPs and highly sensitive to concentrations of 0.6 and 0.9 μg ml−1 of ethidium bromide (EtBr) and 64 to 128 μg ml−1 of GM@g-GNPs and KAN@g-GNPs. The findings demonstrate that all strains were responsive to moderate nanoparticle concentrations. The results inhibited the efflux pump performance of the drug-loaded g-GNPs. Therefore, the unique design of these nanoparticles (GM@g-GNPs and KAN@g-GNPs) improved the antimicrobial properties, which has great potential for the treatment and care of severe pneumonia.

Synergistic Antibacterial Potential of Greenly Synthesized Silver Nanoparticles with Fosfomycin Against Some Nosocomial Bacterial Pathogens

A considerable number of morbidities and fatalities occur worldwide as a result of the multidrug resistant microorganisms that cause a high prevalence of nosocomial bacterial infections. Hence, the current investigation was conducted to evaluate the antibacterial potency of green fabricated silver nanoparticles (AgNPs) against four different nosocomial pathogens. The flower extract of Hibiscus sabdariffa mediated green fabrication of AgNPs and their physicochemical features were scrutinized using different techniques. Antimicrobial activity of the biogenic AgNPs and their synergistic patterns with fosfomycin antibiotic were evaluated using disk diffusion assay. UV spectral analysis affirmed the successful formation of AgNPs through the detection of broad absorption band at 395 and 524 nm, indicating the surface plasmon resonance of the biofabricated AgNPs. In this setting, the biofabricated AgNPs demonstrated average particle size of 58.682 nm according to transmission electron microscope (TEM) micrographs. The detected hydrodynamic diameter was higher than that noticed by TEM analysis, recording 72.30 nm in diameter and this could be attributed to the action of capping agents, which was confirmed by Fourier Transform Infrared (FT-IR) analysis. Disk diffusion assay indicated the antibacterial potency of biogenic AgNPs (50 μg/disk) against Enterobacter cloacae, Methicillin-resistant Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli strains with relative inhibition zone diameters of 12.82 ± 0.36 mm, 14.54 ± 0.15 mm, 18.35 ± 0.24 mm and 21.69 ± 0.12 mm, respectively. In addition, E. coli was found to be the most susceptible strain to the biogenic AgNPs. However, the highest synergistic pattern of AgNPs-fosfomycin combination was detected against K. pneumonia strain recording relative synergistic percentage of 64.22%. In conclusion, the detected synergistic efficiency of AgNPs and the antibiotic fosfomycin highlight the potential for utilizing this combination in the biofabrication of effective antibacterial agents against nosocomial pathogens.

Effect of carbon nano colloid and its synergism with some antibiotics on Klebsiella pneumonia isolated from UTI of pregnant women

Recently, Klebsiella pneumoniae has become a serious pathogen due to the serious diseases it causes including urinary tract infections especially in pregnant women pneumonia, liver abscess and gastrointestinal. Recent research has tried to find new ways to confront the resistance of these bacteria against different types of antibiotics. Out of 150 isolates that were isolated from urinary tract infections for pregnant women 24 were Klebsiella spp. Molecularly, K. pneumoniae isolates were identified as 16SrRNA of Klebsiella pneumoniae by using polymerase chain reaction. Carbon nano colloid was prepared to investigate the effect of its synergy with antibiotics on the growth of Klebsiella pneumoniae, resistant to a number of antibiotics. The results showed that the highest percentage of the number of bacterial isolates was in the age group 26-30 years. Molecular diagnostics showed that 17 of K. pneumoniae isolates gave a molecular size 274 base pair when PCR was performed using the primer targeting 16SrRNA. Two strains of Klebsiella pneumonia were selected as the most resistant isolates against antibiotics. Multiple concentrations of carbon nanoparticles were synergized with antibiotics and the results showed a broad effect in inhibiting the growth of bacterial isolates. Higher is the concentration of nanoparticles, higher is the sensitivity of Klebsiella pneumonia. The results recorded highest inhibition zoon of 35 mm in Kl.1 isolate and 34 mm in Kl.2 isolate at concentration (1:4) of carbon nanoparticles and Ceftriaxon antibiotic. The concentration of (1:4) of amikacin antibiotic and carbon nanoparticles recorded inhibition zoon (40 and 38 mm) of Kl.1 and Kl.2. The results of the synergistic effect of the antibiotic Gentamicin with carbon nanoparticles showing inhibition zoon diameters were 39 and 28 of the two isolates Kl.1 and Kl.2 respectively.

2192. Clinical and Molecular Characteristics of Severe Respiratory Syncytial Virus Pneumonia in Critically Ill Adults

Abstract Background Respiratory syncytial virus (RSV) has been increasingly recognized as a frustrating cause of morbidity and mortality in adults. However, the clinical impact and molecular characteristics of severe RSV-associated pneumonia in critically ill adult patients have rarely been addressed. Methods This study, nested in a prospective cohort of severe pneumonia, was conducted at a 2,700-bed tertiary care hospital and comprised two parts. In part 1, the clinical characteristics of severe RSV-associated pneumonia were compared with severe influenza virus (IFV)-associated pneumonia between 2010 and 2019. In part 2, we performed phylogenetic and amino acid analyses of the G protein of RSV strains from three groups of different infection severity between 2015 and 2019 (Figure 1). Figure 1.Clinical samples for whole-genome sequencing in part 2. Results In part 1, 92 RSV- and 163 IFV-positive patients were identified. Structural lung diseases, diabetes mellitus, and malignancy were common underlying diseases in both groups. Immunocompromise (57.6% vs. 34.4%, p < 0.001) and hospital acquisition (47.8% vs. 23.9%, p < 0.001) were significantly more common in the RSV group. Clinical manifestations at diagnosis between the groups were generally similar. The mortalities of patients in both groups were similarly high (Table 1). In part 2, 26 RSV strains from three groups (group 1: 11 strains, group 2: 8 strains, and group 3: 7 strains) were analyzed. All isolated RSV-A and -B strains belonged to the ON1 and the BA9 genotypes, respectively. The phylogenetic analysis revealed that the adult severe pneumonia strains clustered by contemporary strains rather than other severe pneumonia strains. There were no significantly different genetic variations among the three groups, including the subtype clades, amino acid sequence substitutions, and changes in potential glycosylation sites. Table 1.Characteristic and outcomes of 255 patients with virus-associated severe pneumonia Conclusion Severe RSV pneumonia was more commonly associated with hospital acquisition and immunocompromised status. Overall clinical features and mortalities of the RSV group were comparable to the IFV group. The molecular characteristics of RSV strains from the adults with severe pneumonia were not distinct from strains from non-pneumonic adults or children, underscoring that the severity of RSV respiratory tract infection is mainly determined by host factors, not by viral factors. Disclosures All Authors: No reported disclosures.

Molecular Characterization and Antibiogram of Selected Pathogens Isolated from Streams and Wells Water Sources in Three Local Government Areas of Rivers State, Nigeria

Aims: Reliance on unhealthy water sources such as hand dug wells and streams have led to the occurrence of waterborne diseases such as amoebic dysentery, gastroenteritis, typhoid fever and cholera among several communities in Rivers State. This study tends to identify selected multidrug resistant pathogens isolated from streams and wells water sources in three Local Government Areas of Rivers State using molecular techniques.
 Methodology: A total of 48 well and stream water samples were collected aseptically from 24 sampling sites in Ikwerre, Emohua and Etche Local Government Areas of Rivers State. Samples were analysed using membrane filtration technique for total heterotrophic bacterial count and total coliform count. The well and stream water samples were also cultured for E. coli, Salmonella and Vibrio sp. Antibiotic sensitivity test of the isolates was carried out using the disk diffusion method and multidrug resistant isolates were identified using PCR-based techniques (16S rRNA).
 Results: The results of this study showed that total aerobic heterotrophic bacteria count occurred more in Emohua LGA for both well and stream water sources with bacterial count of 1.71 x104 cfu/ml for well water samples and 2.35 x 104 cfu/ml for stream water samples. The mean fungal count of the stream water samples was highest in Emohua LGA with 2.55 x 104 cfu/ml followed by Ikwerre LGA which had 4.20 x 103 cfu/ml and Etche LGA with the least count of 1.80 x 102 cfu/ml. All the isolated bacteria species were found to be resistant to more than 50% of the antibiotics used with highest Multi Antibiotic Resistant Index of 0.625. multidrug resistant bacterial isolates identified include Vibrio sp strain 201707CJKOP-Y162 (MG593726), Bacillus sbtilis clone N55 (JQ622582), Chryseobacterium sp strain CB2915-325-DE_0621 (MH512534), Enterobacter sp strain AB55 (MF407145), Klebsiella pneumonia strain M792-16(MH680830), Shigella sonnei strain AR_0030(CP032523), Escherichia coli strain WECHEC025943(CP027205) and Salmonella bongori strain KC153129.116 (MG663494).
 Conclusion: Access to good quality or potable drinking water and efficient sanitary practices are fundamental to human health and economic development. The occurrence of multidrug resistant pathogenic bacterial isolates in natural water sources requires serious routine evaluation in order to forestall the outbreak of waterborne disease epidemics.

Sensitivity of <>iStreptococcus pneumoniae</i> to antibiotics and the sex of the patient: A systematic review and meta-analysis

BACKGROUND: The spread of microbial resistance to antibiotics is a recent global problem, which has become more acute in recent years because of a significant increase in the consumption of antibiotics, against the background of the COVID-19 pandemic. A direct consequence of the spread of antibiotic-insensitive strains of pneumococci limits the treatment options for such patients and deterioration of the prognosis.
 AIM: To determine whether sex is a factor associated with the development of diseases caused by antibiotic-resistant strains of Streptococcus pneumoniae.
 MATERIALS AND METHODS: Using the electronic databases PubMed, ScienceDirect, and Google Scholar, a search was conducted for articles published from January 1980 to December 2020, and studies in English and Russian were selected. The selection of articles and meta-analysis was based on the recommendations of the PRISMA Group and MOOSE. After combining the data, the odds ratio (OR) was calculated with a 95% confidence interval (95% CI). Heterogeneity was assessed.
 RESULTS: After applying the exclusion criteria, 41 publications covering 16635 patients with invasive and non-invasive forms of pneumococcal infection were selected for analysis. Of these, 36 case-control studies and 5 cross-sectional studies were identified. Accordingly, the sex of the patient does not affect the frequency of isolation of pneumococcal strains insensitive to penicillin (odds ratio [OR]=0.92, 95% confidence interval [CI] 0.821.03, I2=7%), resistant to penicillin (OR=0.85, 95% CI 0.671.07, I2=1%), and insensitive to erythromycin (OR=0.80, 95% CI 0.511.24, I2=0%). Male sex is associated with pneumococcal resistance to levofloxacin (OR=1.85, 95% CI 1.033.33, I2=0%).
 CONCLUSIONS: The sex of the patient is not a factor associated with the isolation of S. pneumonia strains insensitive and resistant to penicillin and erythromycin. Moreover, the male sex probably increases the chance of isolation of levofloxacin-resistant pneumococci in adults with invasive pneumococcal infections.

Comparative Study of Antimicrobial Activity of Silver, Gold, and Silver/Gold Bimetallic Nanoparticles Synthesized by Green Approach.

Nanotechnology is one of the most recent technologies. It is uncertain whether the production of small-size nanoparticles (NPs) can be achieved through a simple, straightforward, and medicinally active phytochemical route. The present study aimed to develop an easy and justifiable method for the synthesis of Ag, Au, and their Ag/Au bimetallic NPs (BNPs) by using Hippeastrum hybridum (HH) extract, and then to investigate the effects of Ag, Au, and their Ag/Au BNPs as antimicrobial and phytotoxic agents. Ag, Au, and their Ag/Au BNPs were characterized by UV-visible spectroscopy, FT-IR spectroscopy, XRD, EDX, and SEM analysis. XRD analysis conferring to the face of face-centered cubic crystal structure with an average size of 13.3, 10.72, and 8.34 nm of Ag, Au, and Ag/Au BNPs, respectively. SEM showed that Ag, Au, and Ag/Au BNPs had spherical morphologies, with calculated nano measurements of 40, 30, and 20 nm, respectively. The EDX analysis confirmed the composition of elemental Ag signal of the HH-AgNPs with 22.75%, Au signal of the HH-AuNPs with 48.08%, Ag signal with 12%, and Au signal with 38.26% of the Ag/Au BNPs. The Ag/Au BNPs showed an excellent antimicrobial efficacy against Gram-positive Staphylococcus aureus, Actinomycetes meriye, Bacillus cereus, Streptococcus pyogenes, Methicillin-resistant Staphylococcus aureus, Micrococcus luteus, Streptococcus pneumonia, and Gram-negative Klebsiella pneumonia, Escherichia coli, and Serratia marcescens bacterial strains, as well as against three fungal strains (Aspergillus niger, Aspergillus fumigatus, and Aspergillus flavus) compared to HH extract, HH-AgNPs, and HH-AuNPs. However, further investigations are recommended to be able to minimize potential risks of application.

New thiazole-based bis(Schiff bases) linked to arene units as potential MRSA inhibitors

A new series of thiazole-based bis(Schiff bases) attached to different arene units were efficiently prepared using a three-component tandem protocol. The proposed protocol involved the reaction of aromatic aldehydes, thiosemicarbazide, and bis(α-haloketone) to produce the desired products. The target hybrids were formed by an initial thiosemicarbazone formation in ethanol at 80 °C for 120–150 min, followed by triethylamine-mediated Hantzsch thiazole synthesis in dioxane at 100 °C for 150–180 min. The new hybrids were screened against diverse bacterial strains. The hybrids attached to p-Cl, p-Br, and p-Me had more effective efficacy than ciprofloxacin against S. aureus, and E. coli strains, while they had comparable efficacy to ciprofloxacin against S. mutans, and K. pneumonia strains. Their MIC/MBC values ranged between 1.3–3.2 and 2.6–6.5 µM, respectively, against the previous strains. Additionally, they displayed more effective MRSA inhibitory activity than linezolid with MIC/MBC values in the range of 3.0–21.3 µM.

Drug resistance patterns of Klebsiella pneumonia strains isolated from Shaoxing City, Zhejiang Province in 2019: a multi-centre retrospective study

We retrospectively collected drug susceptibility data of Klebsiella pneumoniae from six tertiary hospitals in Shaoxing City in 2019 and performed a comparative analysis of drug resistance among different hospitals, sexes, ages, and specimens. In total, 1954 strains were identified. The antibiotic resistance rate varied from 4.42% to 36.18%. Most K. pneumoniae were still susceptible to carbapenems and tigecycline, with resistance rates of less than 10%. Drug resistance was relatively mild in Shaoxing Traditional Chinese Medicine Hospital and Shaoxing Maternal and Children Health Hospital, but most severe in Affiliated Hospital of Shaoxing University. Specimens were primarily obtained from elderly and male patients, and the resistance rate increased with age. The specimens were mostly collected from the respiratory and urinary tracts. No carbapenem-resistant strains were collected in 112 isolates from patients under 20 years of age. The ratio of carbapenem-resistant K. pneumoniae isolates was highest in blood-isolated strains (23.86%), and that of extended-spectrum beta-lactamase positive strains was highest in non-blood-sterile body fluids (37.37%). The resistance spectrum of K. pneumoniae varied between hospitals in the same area. Elderly and male patients, non-sterile body fluids, and blood source strains should be seriously considered in empirical treatment. Highlights Prevention and control should be strengthened in hospitals with high rate of drug resistance. Strengthen screening of drug-resistant bacteria in specific populations. Transferred patients should be alerted to the bacterial drug resistance status.

Prevalence of antibiotic resistance genes bla-CTX-M, bla-SHV, bla-TEM in enterobacteria strains isolated from perinatal center patients

Relevance A common mechanism of resistance is the synthesis of enzymes that inactivate the antibiotic (AB). Since its discovery at the end of the 20th century, ESBLs have spread widely throughout the world. Representatives of this group of complex protein compounds have common properties of hydrolysis of ß-lactam antibiotics and differ from each other in amino acid sequence. The genetic determinants that determine their synthesis are the bla-CTX-M, bla-SHV, and bla-TEM genes. Aims. To assess the prevalence of bla-CTX-M, bla-SHV, bla-TEM genes in antibiotic-resistant strains of enterobacteria isolated from samples of patients of the perinatal center. Materials & Methods. We studied 135 strains of ESBL-producing enterobacteria isolated during microbiological monitoring from January 01, 2020 to December 31, 2021. Biological material (feces (92), blood (1), urine (5), cervical canal discharge (33), last (4)) came from patients of the perinatal center (43 women and 92 newborns), examined both for clinical indications and during local microbiological monitoring. Species identification of isolated microorganisms was carried out by bacteriological method, detection of antibiotic resistance genes was carried out using real-time PCR. Results. In 87 cases (64.4%), the studied genetic determinants of antibiotic resistance were successfully identified. Of the 26 studied strains of Klebsiella pneumonia, 24 (92.3%) were able to establish the determinants of resistance to AB, 50% of which are represented by bla-CTX-M. Out of 66 Escherichia coli, 59 (89.33%) had a genetic profile of antibiotic resistance, which was also dominated by bla-CTX-M (67.80%). However, in the Enterobacter cloacae group, it was possible to determine the presence of the studied genes only in 8.10% of cases. K. pneumoniae carrying three antibiotic resistance genes bla-CTX-M, bla-SHV, bla-TEM was isolated once from a sample of the cervical canal of a woman aged 27 years. E. coli strains carrying the CTX-M gene were isolated from 3 mother-child pairs out of 135 cases: in mothers – from the discharge of the cervical canal in the third trimester of pregnancy, in newborns – from feces in the first week of life, which can indicate possible transmission of an AB-resistant microorganism either in utero or through the birth canal. Conclusions. Thus, in the course of the study, determinants of antibiotic resistance of enterobacteria isolated from patients of the perinatal center were identified in 64.4% of cases. The dominant gene leading to the occurrence of AD among ESBL is the bla-CTX-M gene. The number of strains with an established genetic profile of resistance to AB is less among Enterobacter cloacae (p<0.001). In order to study the genetic profile in more detail and to identify the mechanisms for the formation of antibiotic resistance, it is necessary to expand the detection of observed genes

Elucidation of antibacterial activity of Bacillus sp. and Alcaligenes sp. metabolites against multidrug-resistant bacteria

Different resistance mechanisms are involved in exhibiting resistance to different groups of antibiotics. Researchers are searching for new therapeutic options to encounter the emerging trend of microbial resistance. Bacteria were isolated from the extreme environment of Cholistan Desert and were screened for characterization. Potential metabolites that showed broad-spectrum activity were partially purified using silica gel chromatography and determined their minimum inhibitory concentration. A collection of 50 bacterial isolates from soil samples was screened for metabolite production and among them isolate R19 of Bacillus sp. and isolate A8 of Alcaligenes sp. had high similarity with strong antimicrobial metabolite producers. The growth of A8 was stable at slight acidic pH while R19 was best at neutral pH. Similarly, the best growth of A8 was observed at 37 °C while R19 at 35 °C. Minimum inhibitory concentration of purified compounds of Bacillus sp. were determined at concentration range of (3.12 – 100 %) against multidrug-resistant (MDR) strains of Shigella, Enterobacter aerogenes, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumonia and produced 10 – 25 mm zone of inhibition. Metabolites of Alcaligenes sp. were sufficient to inhibit the growth of all selected MDR bacteria at concentrations 12.25 – 100 % and shows 10 – 20 mm zone of inhibition. Bacillus sp. and Alcaligenes sp. can be used as producers of potential antibacterial metabolites. Proper utilization of selected metabolites can be helpful in combating emerging drug resistant pathogenic bacteria. In addition, further proteomic analysis and structural insight should be considered to elaborate their active ingredients and its efficacy.

Genetic fingerprinting and profile analysis of virulence genes in XDR clinical isolates of Klebsiella Pneumoniae.

Klebsiella pneumoniae, a leading cause of hospital- and community-acquired infections, requires the acquisition of drug resistance and virulence for survival in evading the host's immune responses. The investigation looks at the molecular diversity of 30 clinical isolates using rep-PCR DNA fingerprinting and the association between drug resistance and virulence genes. Isolates were cultured using basic bacteriological techniques, while antimicrobial susceptibility test and ID confirmation were made by Vitek 2 Compact Automated System (BioMerieux, Marcy L'Etoile, France). DNA used for PCR reactions was extracted with Qiagen DNA extraction kit according to the manufacturer's guidelines, while molecular genotyping by REP-PCR was carried out according to previously described methods. Some virulence genes and capsular serotypes, ybtS, mrkD, entB, rmpA, K2, Kfu, alls, iutA, and magA, were amplified by multiplex PCR. The majority (60%) of the isolates were MDR, others were XDR (37%) and susceptible strains (3%). Additionally, resistance was high (73%) for meropenem and lower (40%) for imipenem, while 97% were susceptible to ertapenem and azithromycin. DNA fingerprinting by rep-PCR showed polymorphic loci sizes that ranged from 100-2000 bp-, and phylogenetic analysis placed the isolates in seven clades with 40-96%. There was a 75% phylogenetic relatedness to antimicrobial resistance, but no specific pattern of relatedness was seen between virulence genes for the K. pneumoniae strain. Regulator mucoid phenotype A (rmpA) gene was not amplified in any of the isolates. This study further confirms the presence of both MDR and XDRK. pneumoniastrains. Isolates exhibited genetic diversity in phylogenetic patterns and carriage of virulence with relatedness by susceptibility to antimicrobials. Therefore, circulation could pose a risk to public health.

PB2256: BACTERIAL BLOODSTREAM INFECTIONS AND ANTIMICROBIAL SUSCEPTIBILITY PATTERN IN PATIENTS WITH ACUTE LEUCAEMIA

Background: Currently, there is a trend towards an increasing proportion of Gram-negative microorganisms, including Enterobacterias. Escherichia coli and Klebsiella pneumoniae constitute the major part in the structure of bloodstream pathogens. One important mechanism of Enterobacterias’ resistance is the production of extended-spectrum beta-lactamases (ESBL), AmpC β-lactamases and carbapenemases. Aims: Determination of the antibiotic resistance profile of bloodstream pathogens in patients with acute leukaemia and evaluation of the efficacy of starting antibiotic therapy regimens. Methods: The study included 69 cases of bloodstream infections, confirmed by bacteriological blood testing in patients with acute leukaemia between January 2020 and January 2022, 46.4% of which were male and 53.6% were female, with a median age of 44 years. All patients had myelotoxic agranulocytosis at the time of infectious complications. Results: During the study period and according to the bacteriological examination of blood, 58 strains of E. coli and Kl. pneumoniae were detected. The antibiotic sensitivity pattern is shown in the figure. Bloodstream infection caused by E. coli was detected in 23 cases (32.8%), herewith ESBL production was detected in 47.8% of E. coli strains. In the scope of the empirical antibiotic therapy, the 4th generation cephalosporin (cefepime) was used in 39.1% of cases or carbapenem (meropenem) in 60.9% of cases in combination with the 3rd generation aminoglycoside (amikacin). Herewith the empirical antibiotic therapy was considered as rational in 78.3% of cases, whereas in the remaining cases escalation was essential. The use of the 4th generation cephalosporin (cefepime) in the scope of the empirical therapy was ineffective in 55.6% of cases. Due to the therapy in 95.7% of cases the patient’s condition was stable, and in 4.3% of cases led to a fatal outcome. Bloodstream infection caused by Kl. pneumoniae was detected in 35 cases (50%), and resistance to carbapenems was reported in 68.6% of strains of the Kl. pneumoniae. The share of ESBL-producing Kl. pneumonias trains was 40%, while the proportion of Enterobacteriaceae strains, susceptible to extended-spectrum cephalosporins and carbapenems, reached only 8.8%. During the therapy in 72.4% of cases the patient’s condition stabilised, and in 27.6% of cases a fatal outcome was recorded. In all cases of fatality сarbapenem-resistant strains, including panresistant strains (5.9%) acted as a causative agent. Summary/Conclusion: The most frequent causative agents of bloodstream infections in acute leukaemia patients during myelotoxic agranulocytosis are the Gram-negative bacteria E. coli and Kl. pneumoniae. The empirical antibiotic therapy regimens including 3rd generation cephalosporins (cefepime) was ineffective in 55.6% of cases, as 47.8% of isolated E. coli strains were generating ESBL. This increases the relevance of using carbapenems. Resistance to carbapenems was reported in 68.6% of strains of Kl. pneumoniae. This indicates a high prevalence of carbapenem-resistant strains in the haematological hospital, as well as the low efficacy of empirical antibiotic therapy, including both cephalosporins and carbapenems.

Copper-doped magnesium ferrite and its composite with rGO: Synthesis, characterization, and degradation of organic effluents and antibacterial study

Magnesium ferrite (MgF), copper doped magnesium ferrite (CMgF), and their composite with rGO sheets were used to study the degradation of the organic pollutants and to perform antibacterial activity. The photocatalysts were prepared by the co-precipitation technique and characterized using X-rays diffraction (XRD), scanning electron microscopy (SEM) UV–visible, and fourier transfrom infrared microscopy (FT-IR), and photoelectrochemical analysis. The structure of the nanomaterials was confirmed via XRD. The functional group detection was carried out via FT-IR spectroscopy. The SEM technique was used to confirm the surface morphology of the prepared nanocatalysts. UV–Visible spectroscopy was used to measure the absorbance during the degradation experiment. The percentage photodegradation by CMgF@rGO of methylene blue was 92.4%, and that of benzimidazole was 50%. CMgF@rGO also showed better antibacterial activity against bacterial strains of Klebsiella pneumonia and Staphylococcus aureus. The rGO layers can enhance the photodegradation efficiency of copper doped magnesium ferrite due to an increase in surface area. The EIS study revealed that CMgF@rGO illustrated 2.59 and 1.57 times less charge transfer resistance than MgF and CMgF samples. The CMgF@rGO composite separately showed 9.7-fold and 3.9-fold greater transient photocurrent response than MgF and CMgF samples. A scavenging experiment was carried out to determine the most reactive species; and hydroxyl radicals were found to be highly active species, and electrons were the least reactive species.

Inosine and D-Mannose Secreted by Drug-Resistant Klebsiella pneumoniae Affect Viability of Lung Epithelial Cells.

The antibiotic resistance rates of Klebsiella pneumoniae have been steadily increasing in recent years. Nevertheless, the metabolic features of the drug-resistant Klebsiella pneumoniae and its associated benefits for bacterial pathogenicity are far from expounded. This study aims to unravel the unique physiological and metabolic properties specific to drug-resistant K. pneumoniae. Using scanning electron microscopy (SEM), we observed a thicker extracellular mucus layer around a drug-resistant K. pneumonia strain (Kp-R) than a drug-sensitive K. pneumonia strain (Kp-S). Kp-R also produced more capsular polysaccharide (CPS) and biofilm, and appeared to have a significant competitive advantage when co-cultured with Kp-S. Moreover, Kp-R was easier to adhere to and invade A549 epithelial cells than Kp-S but caused less cell-viability damage according to cell counting kit-8 (CCK-8) tests. Immunofluorescence revealed that both Kp-R and Kp-S infection destroyed the tight junctions and F-actin of epithelial cells, while the damage caused by Kp-S was more severe than Kp-R. We detected the extracellular metabolites secreted by the two strains with UHPLC-Q-TOF MS to explore the critical secretion products. We identified 16 predominant compounds that were differentially expressed. Among them, inosine increased the viability of epithelial cells in a dose-dependent manner, and an A2AR antagonist can abolish such enhancement. D-mannose, which was secreted less in Kp-R, inhibited the viability of A549 cells in the range of low doses. These findings provide potential targets and research strategies for preventing and treating drug-resistant K. pneumoniae infections.

Microbiological and Clinical Characteristics of Bloodstream Infections in General Intensive Care Unit: A Retrospective Study.

BackgroundBloodstream infections (BSI) are one of the common causes of morbidity and mortality in hospitals; however, the pathogenic spectrum and bacterial antibiotic resistance vary across the world. Therefore, identifying the pathogenic spectrum and changes in bacterial antibiotic resistance is critical in controlling BSI and preventing the irrational use of antibiotics. This study evaluated the microbiological and clinical data of BSI patients in the intensive care unit (ICU) of Tianjin Medical University General Hospital in Tianjin, China, to guide the selection of empirical antibiotic therapy.MethodsThis study retrospectively analyzed the distribution and antibiotic resistance of pathogens based on the clinical data of BSI patients presented in the ICU of a tertiary teaching hospital from 2018 to 2020. Test performance for the prediction of pathogen species was assessed by receiver operating characteristic (ROC) analysis.ResultsThe analysis of the data of 382 BSI cases (10.40 cases per thousand patient day) revealed the most frequently isolated microorganisms to be Klebsiella pneumonia (11.52%), followed by Escherichia coli (9.95%), Staphylococcus epidermidis (9.95%), Candida parapsilosis (8.12%), and Enterococcus faecium (8.12%). Out of the isolated E. coli and K. pneumonia strains, 52.63, and 36.36%, respectively, were extended-spectrum β-lactamase (ESBL) positive. The antibiotic-resistance rate of the ESBL-positive strains was 30.56% for piperacillin/tazobactam, 5.56% for imipenem, and 11.11% for tigecycline. In addition, most A. baumannii belonged to the group of multidrug-resistant (MDR) strains, with an antibiotic-resistance rate of 90.48% for meropenem and 16.00% for amikacin. However, polymyxin-resistant A. baumannii strains were not detected. Four strains of methicillin-resistant S. aureus (MRSA) (4/21, 19.05%) and one strain of vancomycin-resistant enterococci (VRE) were detected, with a resistance rate of 4.76 and 2.32%, respectively. Among the isolated 55 fungal strains, C. parapsilosis was the most common one (30/55, 56.36%), with an antibiotic-resistance rate of 5.77% for voriconazole, fluconazole, and itraconazole. The presence of amphotericin B-or flucytosine-resistant strains was not observed. Compared with the patients with Gram-positive and fungal pathogens, patients with Gram-negative bacteria exhibited the highest sequential organ failure assessment (SOFA) score (P < 0.001), lowest Glasgow Coma Scale (GCS) (P = 0.010), lowest platelet (PLT) value (P < 0.001), highest plasma creatinine (Cr) value (P = 0.016), and the highest procalcitonin (PCT) value (P < 0.001). The AUC in the ROC curve was 0.698 for the differentiation of Gram-negative BSI from Gram-positive BSI. A cutoff value of 8.47 ng/mL for PCT indicated a sensitivity of 56.9% and a specificity of 75.5%. The AUC in the ROC curve was 0.612 for the differentiation of bacteremia from fungemia. A cutoff value of 4.19 ng/mL for PCT indicated a sensitivity of 56.8% and a specificity of 62.7%.ConclusionAmong the bloodstream infection strains in ICU, Gram-negative bacteria have the highest drug resistance rate, and will cause more serious brain damage, renal function damage and thrombocytopenia. So clinician should pay more attention to the treatment of Gram-negative bacteria in patients with bloodstream infection in ICU. The test index of PCT can be used to distinguish Gram-negative bacteremia from Gram-positive and bacteremia from fungemia but not as an effective indicator, thereby indicating the need for further large-scale research.

High Prevalence of Klebsiella pneumoniae in Greek Meat Products: Detection of Virulence and Antimicrobial Resistance Genes by Molecular Techniques.

Background: The presence of antimicrobial-resistant pathogens such as Klebsiella pneumoniae strains in the food supply is dangerous. The aim of this study was to assess the prevalence of Klebsiella pneumonia strains in Greek meat products and evaluate their phenotypes and genotypes. Methods: One hundred and ten meat specimens were cultured for the isolation of K. pneumoniae. In positive specimens, PCR (Polymerase Chain Reaction) analysis was performed to confirm the presence of K. pneumoniae. Genotypic and phenotypic evaluation of the isolated strains included multiplex immunoassay for the detection of carbapenemases, and PCR screening for the detection of resistance and virulence genes. Results: K. pneumoniae strains were recovered in 90 (81.8%) meat samples. The ecpA gene was identified in 30 (33.3%) isolates, while the fimH-1 and mrkA genes were present in 15 (16.7%) and 65 (72.2%) isolates, respectively. Sixty-five K. pneumoniae isolates (72.2%) were found to carry at least one resistance gene; of these, the blaNDM-like was the most commonly identified gene in 40 (61.5%) isolates, followed by the blaOXA-48 like gene in 20 isolates (30.8%). Conclusions: A high frequency of foodborne K. pneumoniae in Greece was found. Our results indicate that most strains carried resistance and virulence genes, indicating a high pathogenic potential and a significant risk to human health.

Metabolic properties, gene functions, and biosafety analysis reveal the action of three rhizospheric plant growth-promoting bacteria of Jujuncao (Pennisetum giganteum).

This study aimed to identify the specific genes associated with plant growth promotion and cadmium tolerance in three bacteria strains associated with Pennisetum giganteum as well as to determine their biosafety levels in their potential use as biofertilizers for promoting plant growth and phytoremediation activities. The plant growth-promoting (PGP) abilities of Enterobacter cloacae strain RCB980 (A3), Klebsiella pneumonia strain kpa (A4), and Klebsiella sp. strain XT-2 (A7) were determined by a growth promotion trial and through testing for PGP traits such as 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase enzyme production, phosphorus solubilization, siderophore synthesis, and indole-3 acetic acid (IAA) production. The genes that potentially contribute to the beneficial activities of these three strains were identified through an analysis of their genomes. To establish the biosafety of the candidate PGPB, a pathological study was undertaken whereby 20 Kunming mice were injected intraperitoneally to study and analyze the effects of the strains on growth and lung paraffin sections of the mice. The strains had no obvious toxicity effect on the tested mice and were therefore not considered as highly virulent strains. These strains are thus considered non-toxic, safe, and highly recommended for use in environmental remediation strategies and agricultural production.