Multidrug-resistant Klebsiella Pneumonia Research Articles

Known case of ESRD due to IgA nephropathy with myelodysplastic syndrome having perinephric hematoma and disseminated multi-drug resistant Klebsiella pneumonia infection in urinary tract, gastrointestinal tract and testes following living donor kidney transplantation: The strength of multidisciplinary team management

A 34 years old man, had increasing pain over grafted kidney with low urine output on post-operative ‘Day 7’ following living donor kidney transplantation. He was a known case of IgA nephropathy with end stage renal disease and Myelodysplastic Syndrome (MDS). CT abdomen revealed perinephric hematoma; cast effect on graft kidney; and the density over grafted kidney was decreased suggestive of rejection. He also had disseminated multi-drug resistant Klebsiella pneumonia infections in urinary tract, gastrointestinal tract and orchitis. Multi-disciplinary team’s management which includes nephrologists, general physicians, hematologists, uro-surgeons, vascular surgeons, radiologists, microbiologists and anesthetists saves patient’s life as well as transplant kidney.

In Vitro antibiotic combinations of Colistin, Meropenem, Amikacin, and Amoxicillin/clavulanate against multidrug-resistant Klebsiella pneumonia isolated from patients with ventilator-associated pneumonia

BackgroundHospital infections such as ventilator-associated pneumonia (VAP) due to multidrug-resistant Klebsiella pneumoniae (MDR-KP) strains have increased worldwide. In addition, biofilm production by these resistant isolates has confronted clinicians with higher treatment failure and infection recurrence. Given the paucity of new agents and limited data on combination therapy for MDR-KPs, the present study sought to evaluate the in vitro activity of several antibiotic combinations against planktonic and biofilm MDR-KPs isolated from patients with VAP.ResultsAll 10 carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates demonstrated multidrug resistance against the tested antibiotics. At planktonic mode, combinations of colistin-meropenem and amoxicillin/clavulanate in combination with meropenem, colistin, or amikacin showed synergism against 60–70% isolates. On the other hand, in the biofilm state, colistin-based combinations exhibited synergism against 50–70% isolates and the most effective combination was colistin-amikacin with 70% synergy.ConclusionsThe results revealed that combinations of amoxicillin/clavulanate with colistin, meropenem, or amikacin in the planktonic mode and colistin with amoxicillin/clavulanate, meropenem, or amikacin in the biofilm mode could effectively inhibit CRKP isolates, and thus could be further explored for the treatment of CRKPs.

A Study on IFN-γ and IL-10 Gene Expression Changes in Gallus Gallus Domesticus Embryo Infected with Klebsiella Pneumoniae and its Possible Alteration by Bakreshwar Hot Spring Water

Background: Hot spring's water is enriched with minerals which has many therapeutic values. Bakreshwar is well known for its ten hot springs of varying temperatures (35°C-71°C). Bathing repeatedly in hot springs can help us to fight against skin infection, rheumatic disorders, joint pain etc. Objectives: The present study aimed to explore the changes in the gene expression of IL-10 and IFN-γ in the Gallus gallus domesticus embryo, infected with multi-drug-resistant Klebsiella pneumoniae and by using the Bakreshwar hot spring water to make any curative changes in the target gene expression or not. Methodology: 14 days old embryonated eggs of Gallus gallus domesticus was inoculated with freshly prepared 0.5 Mc Farland standard suspension of Klebsiella pneumoniae and curative set was treated with Bakreshwar Hot Spring water, collected from Agnikund (65°C). Then the embryonated eggs were harvested following the Institutional Ethical Committee guidelines and the allantoic fluid was collected. On the next day, RNA extraction was performed and cDNA synthesis followed by RT PCR was performed to study the cytokine gene expression. Results: After infection of chick embryo Gallus gallus domesticus with multi drug resistant Klebsiella pneumoniae, both IL-10 and IFN-γ gene expression was increased, but in curative sets that were challenged with Bakreshwar water, IL-10 gene expression was decreased and IFN-γ was increased. Conclusion: Hot spring water of Bakreshwar has antimicrobial effect on multi drug resistant Klebsiella pneumonia and it can normalize the cytokine balance with prolonged protection with raised IFN-γ.

Multi-drug resistant Klebsiella-induced corneal ulcer following pterygium surgery: a case report

BackgroundManagement of pterygium is dependent on the grading of pterygium and its clinical presentation (inflamed or quiescent), and surgical excision is the final choice of treatment for the pterygium extending beyond the limbus. Infectious keratitis is one of the most commonly reported complications in recent years. To the best of our knowledge, Klebsiella keratitis after pterygium surgery has not been described in the current literature. Here, we report a patient with corneal ulcer formation following pterygium surgical excision.Case presentationA 62-year-old woman presented with complaints of pain, blurred vision, photophobia and redness in her left eye for a month. She had a history of pterygium surgical excision two months ago. Slit-lamp examination showed conjunctival congestion, a central whitish corneal ulcer with a central epithelial defect, and hypopyon. Corneal scraped sample revealed multidrug resistant (MDR) Klebsiella pneumonia and the strain was found to be sensitive to cefoxitin and ciprofloxacin. Intracameral cefuroxime (1 mg/0.1 mL) injection, fortified cefuroxime ophthalmic suspension (50 mg/mL) and moxifloxacin ophthalmic suspension (0.5%) were successfully administered to control the infection. Since residual central stromal opacification remained persistent, final visual acuity did not improve beyond finger counting at two meters.ConclusionsKlebsiella keratitis is a rare and sight-threatening complication following pterygium excision. This report emphasizes the importance of close follow-up examination following pterygium surgeries.

Genetic Diversity of Polymyxin-Resistance Mechanisms in Clinical Isolates of Carbapenem-Resistant Klebsiella pneumoniae: a Multicenter Study in China.

Polymyxin has been the last resort to treat multidrug-resistant Klebsiella pneumonia. However, recent studies have revealed that polymyxin-resistant carbapenem-resistant Klebsiella pneumonia (PR-CRKP) emerged due to the mutations in chromosomal genes or the plasmid-harboring mcr gene, leading to lipopolysaccharide modification or efflux of polymyxin through pumps. Further surveillance was required. In the present study we collected PR-CRKP strains from 8 hospitals in 6 provinces/cities across China to identify the carbapenemase and polymyxin resistance genes and epidemiological features by whole-genome sequencing (WGS). The broth microdilution method (BMD) was performed to determine the MIC of polymyxin. Of 662 nonduplicate CRKP strains, 15.26% (101/662) were defined as PR-CRKP; 10 (9.90%) were confirmed as Klebsiella quasipneumoniae by WGS. The strains were further classified into 21 individual sequence types (STs) by using multilocus sequence typing (MLST), with ST11 being prevalent (68/101, 67.33%). Five carbapenemase types were identified among 92 CR-PRKP, blaKPC-2 (66.67%), blaNDM-1 (16.83%), blaNDM-5 (0.99%), blaIMP-4 (4.95%), and blaIMP-38 (0.99%). Notably, 2 PR-CRKP strains harbored both blaKPC-2 and blaNDM-1. The inactivation of mgrB, associated significantly with high-level polymyxin resistance, was mainly caused by the insertion sequence (IS) insertion (62.96%, 17/27). Furthermore, acrR was inserted coincidently by ISkpn26 (67/101, 66.33%). The deletion or splicing mutations of crrCAB were significantly associated with ST11 and KL47 (capsule locus types), and diverse mutations of the ramR gene were identified. Only one strain carried the mcr gene. In summary, the high IS-inserted mgrB inactivation, the close relationship between ST11 and the deletion or splicing mutations of the crrCAB, and the specific features of PR-K. quasipneumoniae constituted notable features of our PR-CRKP strains in China. IMPORTANCE Polymyxin-resistant CRKP is a serious public health threat whose resistance mechanisms should be under continuous surveillance. Here, we collected 662 nonduplicate CRKP strains across China to identify the carbapenemase and polymyxin resistance genes and epidemiological features. Polymyxin resistance mechanism in 101 PR-CRKP strains in China were also investigated, 9.8% of which (10/101) were K. quasipneumoniae, as determined via WGS, and inactivation of mgrB remained the most crucial polymyxin resistance mechanism, significantly related to high-level resistance. Deletion or splicing mutations of crrCAB were significantly associated with ST11 and KL47. Diverse mutations of the ramR gene were identified. The plasmid complementation experiment and mRNA expression analysis further confirmed that the mgrB promoter and ramR played a critical role in polymyxin resistance. This multicenter study contributed to the understanding of antibiotic resistance forms in China.

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.

Sono-photocatalytic disinfection of high strength multi-drug resistant Klebsiella pneumonia in presence of blue LED-active CdS nanorods

The prevalence of antibiotic resistant pathogenic microbes in wastewater necessitates effective disinfection treatment to protect human health and the environment. Klebsiella pneumoniae is considered as an opportunistic and emerging human pathogen which can develop resistance towards a broad range of antibiotics. In the present study, a hybrid approach merging photocatalysis by CdS nanorods (NRs) with physico-chemical method of acoustic cavitation was investigated to disinfect MDR Klebsiella pneumonia under blue LED irradiation. Various reaction parameters like light intensity, sonication power, catalyst loading, and bacterial load were studied. Effective and complete disinfection was observed with a catalyst loading of 250 mg/L eradicating a bacterial concentration of 106 CFU/mL within 20 mins. Being a hybrid strategy, the catalyst concentration below the optimum (<1xMIC) was also able to provide significant disinfection majorly due to the synergistic effect. Primary mechanism of disinfection was inferred from the escape of intracellular nucleic acids suggesting disruption of cell membrane followed by ROS scavenging experiments which suggested the importance of various ROS species in the decontamination experiments. The stability of photocatalytic efficiency of the CdS nanorods even after multiple cycles of disinfection revealed possibilities of nanomaterial recycling for wastewater disinfection. The results suggest that the hybrid sono-photocatalytic approach can proficiently eliminate harmful multi-drug resistant bacteria and drastically reduce operational time. However, upscaling of the approach to disinfect actual wastewater remains to be investigated for environmental applications.

Pharmacological importance of TG12 from tachykinin and its toxicological behavior against multidrug-resistant bacteria Klebsiella pneumonia

Development of antimicrobial drugs against multidrug-resistant (MDR) bacteria is a great focus in recent years. TG12, a short peptide molecule used in this study was screened from tachykinin (Tac) protein of an established teleost Channa striatus (Cs) transcriptome. Tachykinin cDNA has 345 coding sequence, that denotes a protein contained 115 amino acids; in which a short peptide (TG12) was identified at 83–94. Tachykinin mRNA upregulated in C. striatus treated with Aeromonas hydrophila and Escherichia coli lipopolysaccharide (LPS). The mRNA up-regulation was studied using real-time PCR. The up-regulation tachykinin mRNA pattern confirmed the immune involvement of tachykinin in C. striatus during infection. Further, the identified peptide, TG12 was synthesized and its toxicity was demonstrated in hemolytic and cytotoxic assays using human erythrocytes and human dermal fibroblast cells, respectively. The toxicity study exhibited that the toxicity of TG12 was similar to negative control, phosphate buffer saline (PBS). Moreover, the antibiogram of TG12 was active against Klebsiella pneumonia ATCC 27736, a major MDR bacterial pathogen. Further, the antimicrobial activity of TG12 against pathogenic bacteria was screened using minimum inhibitory concentration (MIC) and anti-biofilm assays, altogether TG12 showed potential activity against K. pneumonia. Fluorescence assisted cell sorter flow cytometer analysis (FACS) and field emission scanning electron microscopy (FESEM) was carried on TG12 with K. pneumonia; the results showed that TG12 significantly reduced K. pneumonia viability as well as TG12 disrupt its membrane. In conclusion, TG12 of CsTac is potentially involved in the antibacterial immune mechanisms, which has a prospectus efficiency in pharma industry against MDR strains, especially K. pneumonia.

Detection of oqxA and oqxB efflux pump genes among nosocomial coliform bacilli: An observational cross-sectional study

Objectives: To identify and test the antibiotic susceptibility of nosocomial coliform bacilli and investigate the presence of oqxA and oqxB genes among the multidrug-resistant (MDR) phenotypes.Methods: One hundred and twenty different healthcare-associated infection samples were collected. Coliform bacilli were isolated, identified by conventional methods, and then antibiotic susceptibility tests were done using the VITEK2 system and disk diffusion methods. OqxAB operon was identified using a conventional PCR-based technique. oqxA and oqxB genes were compared between MDR Klebsiella pneumonia (K. pneumonia) phenotypes and MDR Escherichia coli (E. coli) phenotypes. Besides, oqxAB operons were compared between phenotypes of K. pneumonia and E. coli isolates.Results: Seventy coliform bacilli were isolated with the predominance of K. pneumonia and E. coli. Besides, 82.1% of K. pneumonia strains and 53.3% of E. coli isolates were MDR phenotypes. Significant more oqxB genes alone were found in MDR E. coli than that in MDR K. pneumoniae phenotypes (χ2=10.160, P=0.003). OqxAB operon was significantly more in MDR phenotypes of E. coli than that in the susceptible phenotypes (P<0.001). There was significantly less of this operon in susceptible E. coli isolates than that in susceptible K. pneumoniae isolates (P<0.001). OqxAB positive isolates that were also resistant to fluoroquinolones, tetracycline, trimethoprim, and chloramphenicol, most probably suggested functional pumps.Conclusions: MDR coliform bacilli are strongly implicated in healthcare-associated infection. Attention should be paid to the presence of oqxAB pump, as an important mechanism in the development of resistance against many antimicrobials because it contributes to co-resistance with other categories; therefore, this pump could be a good target for efflux pump inhibitors.

Characterization of Polyvalent Bacteriophages Targeting Multidrug-Resistant Klebsiella pneumonia with Enhanced Anti-Biofilm Activity

Klebsiella pneumoniae causes a variety of human infections including pneumonia. Herein, 3 lytic bacteriophages specific for K. pneumoniae designated ΦKpnM-vB1, ΦKpnP-vB2 and ΦKpnM-vB3 were isolated and characterized. Transmission electron microscopy (TEM) analysis revealed that both ΦKpnM-vB1 and ΦKpnM-vB3 belong to family Myoviridae, while ΦKpnP-vB2 is a member of family Podoviridae. The one-step growth curve showed that ΦKpnM-vB1, ΦKpnP-vB2 and ΦKpnM-vB3 exhibited latent period of 10 min. The average burst sizes were 100, 150 and 120 PFU/cell, respectively. Isolated phages showed high thermal and pH stability. The genomic analysis indicated that ΦKpnM-vB1, ΦKpnP-vB2 and ΦKpnM-vB3 contain dsDNA genome with estimated sizes of 55, 40 and 50 Kbp, respectively. Isolated phages had lytic activity on K. pneumoniae and Escherichia coli strains. Isolated phages were highly efficient in reduction of Klebsiella biofilm suggesting their use to control biofilm formation caused by this pathogen. Isolated ΦKpnM-vB1, ΦKpnP-vB2 and ΦKpnM-vB3 are proposed to be suitable candidates for phage therapy applications. These phages offer an effective solution for treatment of infections caused by these drug-resistant bacteria.

Involvement of AcrAB and OqxAB Efflux Pumps in Antimicrobial Resistance of Clinical Isolates of Klebsiella pneumonia

Introduction: Infections caused by multidrug-resistant Klebsiella pneumonia characterize a major warning throughout the world owing to enhanced mortality and treatment limitations. Efflux pumps have an important role as a mechanism of antibiotic resistance in K. pneumoniae. In the current study, the role of AcrAB and OqxAB efflux pumps to antibiotic resistance was investigated in clinical isolates of K. pneumonia. Materials and Methods: During August 2017-October 2018, 110 clinical strains of K. pneumoniae were obtained from patients referred to the hospitals in Tehran. After microbiological/biochemical identification, and antimicrobial susceptibility test was performed using the disc diffusion method. Then, the minimum inhibitory concentration of ciprofloxacin-resistant K. pneumoniae strains was measured by the broth microdilution method. For investigating the efflux pump mediated drug resistance in K. pneumoniae, the presence, and prevalence of efflux genes (acrA/acrB and oqxA/oqxB) were examined by the Polymerase Chain Reaction (PCR) technique. Results: The results showed that resistance to ciprofloxacin, norfloxacin, gentamicin, kanamycin, cefotaxime, trimethoprim, chloramphenicol, and colistin was 19.09%, 21.81%, 10.0%, 9.09%, 44.54%, 25.45%, 11.81%, and 61.81%, respectively, in K. pneumoniae clinical isolates. The PCR technique demonstrated that the prevalence of acrA/acrB and oqxA/oqxB genes are 58 (52.72%) and 52 (47.27%), respectively. Conclusions: The results of this study reveal that the AcrAB and OqxAB efflux pumps have a major role in the antibiotic resistance of multidrug resistance K. pneumoniae isolates. Therefore, due to the easy transfer of antimicrobial resistance genes, the accurate detection of resistance genes by molecular methods is essential to control the spread of resistant strains.

Unusual Polymicrobial Wound Infections In Healthy Patient After Cesarean Sectio

Cesarean delivery often complicated by surgical site infection, wound infection and endometritis. No study mention Multidrug Resistant Klebsiella pneumonia and Acinetobacter lwofii were isolated.Here we report a rare case of polymicrobial wound infections in healthy patient after Cesarean Sectio caused by Pseudomonas aeruginosa, Multidrug Resistant Klebsiella pneumonia and Acinetobacter iwofii. A 30-year-old woman at 37 weeks gestation (G1P0A0) presented to our hospital for cesarean sectio due to oligohydroamnios and malpresentation. She came to us on the eleventh post-delivery day with discharge from her surgical wound. Intraoperative cultures revealed Pseudomonas aeruginosa, Multidrug Resistant Klebsiella pneumonia and Acinetobacter lwofii.The greatest contribution to risk for surgical site infection was associated with maternal obesity and hypertensive disorder, but she has no risk factor.The polymicrobial combination of our patient’s is unique from previously described studies, in this case all were Gram negative bacteria (Pseudomonas aeruginosa, Multidrug Resistant Klebsiella pneumonia and Acinetobacter lwofii).

ANTIBACTERIAL CHARACTERIZATION OF TITANIUM NANOPARTICLES NANOSYNTHESIZED BY STREPTOCOCCUS THERMOPHILUS

Metals that contain nanomaterials have the potential to be employed in controlling different kinds of infection, however, very limited information is known about their antibacterial properties. This study has been done to investigate the nanosynthesis titanium nanoparticles (TiNPs) using Streptococcus thermophilus and analyzing their biological actions as antibacterial. The bacterial isolates identified using universal primers 16S rRNA; then the 16S rRNA gene nucleotide sequences were aligned with the nucleotide sequences of strains obtained from the GeneBank through the software CLUSTAL X (version 1.82). Titanium nanoparticles were nanosynthesized by adding 0.025M titanium dioxide (TiO2) into cell-free supernatant for Streptococcus thermophilus. TiO2 was used as a precursor for nanobiosynthesis TiNPs. The formation of TiNPs was indicated by the color alteration of the solution from the light brown into dark brown indicates for the production of TiNPs. The Characterization of nanobiosynthesis was accomplished with UV-Visible (absorbance at 377nm), Scanning Electron Microscope, X-ray diffraction, Atomic Force Microscope, Energy-dispersive X-ray spectroscopy was used to distinguish the dimension, form (spherical) by SEM, dispersal (homogenous) and elemental analysis of nanoparticles. Biogenic TiNPs have displayed antibacterial and antibiofilm activity against both multidrugresistant Klebsiella pneumonia and Staphylococcus aureus. As an antibacterial activity, the TiNPs inhibited significantly K.pneumoniae (20 mm) with concentration (500 μg/ml), and S. aureus (16 mm) with the same concentration and increasing the concentration of TiNPs the inhibition zone increased. While as antibiofilm activity of TiNPs using the tube method, the tubes containing bacterial suspension K.pneumoniae and S.aureus with TiNPs, the results demonstrated that the biofilm formation was prevented and removed by the effect of TiNPs.

Tigecycline in CR-Kp Associated VAP with High Dose vs. Conventional Dose: Adverse Events are the Key Superiority-determiner

Background: Multi-drug Resistant (MDR) pathogen Carbapenem-Resistance Klebsiella pneumonia (CR-Kp) associated Ventilator-Associated Pneumonia (VAP) is a serious infectious disease and tigecycline with high or conventional dose, is one of the last resort potential antibiotics for its treatment. Objective: The major objective of this study was to evaluate the key role of adverse events in preferring the better dosing option of tigecycline. Methods: Total 45 middle-aged MDR-CR-Kp associated VAP patients and treated with high (200 mg/day) and conventional dose (100 mg/day) of tigecycline (intravenous) distributed into two groups. Group-wise microbiological eradication rate, secondary infection rate, 30 days mortality rate and dose-related adverse events were analyzed and compared, accordingly. Result: After 5 days, highest microbiological eradication was observed in HD-group (79.17%) than CD-group (47.62%) with low rate of secondary infections (8.33% versus 33.33%). The 30 days mortality rate was relatively higher in HD-group (45.83% versus 38.10%). Severity and frequency of high-dose associated adverse events were higher in HD-group at all parameters than CD-group (elevation of ALT: 33.33%/23.81%; AST: 41.67%/28.57%; bilirubin: 37.50%/19.05%; reduction of blood pH: 45.83%/9.52%, respectively). Conclusion: High dose of tigecycline showed relatively higher therapeutic response in MDR-CR-Kp associated VAP treatment than conventional dose but, with increased rate of adverse events, which questioned its practice.

Detection of Multi-Drug Resistant Klebsiella Pneumoniae in Al-Zahraa University Hospital

Background : the rate of multidrug resistant (MDR) klebsiella pneumonia is increasing worldwide, its detection by available phenotypic methods represents a challenge. However, every lab should estimate its frequency for infection control measures and antibiotic stewardship program. Objective: The aim of the study was to estimate the frequency of MDR klebsiella pneumoniae in Al-Zahraa University Hospital, Cairo, Egypt, and to determine their different phenotypic methods. Methods: frequency of MDR K. pneumoniae isolates from different clinical samples provided to the microbiology laboratory, Al-Zahraa University Hospital, Cairo, Egypt during the period from May 2016 to January 2017 was detected by different phenotypic methods including ESBL detection (ESBL combined disk test, the double disk synergy test and the ESBL NDP test), AmpC production, carbapenemase production, the temocillin disk diffusion test, the Carba NP test, the Blue carba test and the genotypic detection of OXA-48 gene). Results: out of 2058 samples provided to Al-Zahraa University Microbiology Lab, 143 isolates were K. pneumoniae (6.94 %), 120 out of these 143 (83.9 %) were MDR. Their incidence rate (0.1) from the total and (0.8) and from the K. pneumoniae isolates respectively.98.3% of these MDR were ESBL producers, 45.8% were AmpC B lactamase, 39.16% were carbapenem resistant while quinolone and aminoglycoside resistance were 63.6% and 68.3% respectively. Conclusion: continuous laboratory surveillance for different types of resistance in all K. pneumoniae isolates is recommended. ESBL NDP test and blue carba test could be used as routine tests in the microbiology lab for rapid detection of ESBL and carbapenem isolates.

New camphor hybrids: lipophilic enhancement improves antimicrobial efficacy against drug-resistant pathogenic microbes and intestinal worms

Using the Blanc reaction, new derivatives of camphor (1a–g) and camphor sulfonic acid (2a–g) were synthesized. Chemical structures of the new derivatives were supported by IR, 1H-NMR, 13C-NMR, and LC-MS/MS (ESI) spectrometric analyses. The new compounds (1a–g/2a–g) and the parent compounds (a–g) were tested for their antimicrobial efficacy against the following drug-resistant pathogens: methicillin-resistant Staphylococcus aureus (MRSA), multi-drug resistant Klebsiella pneumonia (MDR-Kb), Escherichia coli (FDA control), Acinetobacter baumannii, Pseudomonas aeruginosa, Candida albicans (CLSI: Clinical and Laboratory Standards Institute strain) and Cryptococcus neoformans var. grubii. The linking of camphor to quinoxalin-2,3(1H, 4H)-dione (1a) enhances the antibacterial efficacy approximately 8-folds (MIC: 24 µM) against MRSA. Camphor linking with isatin (1g) increased efficacy against Acinetobacter baumannii by 8-fold (MIC: 26 µM) and by 4-fold (MIC: 51 µM) against MRSA, MDR-Kb, E. coli, P. auruginosa and C. albicans. Among the series, derivatives of benzoin (1e) and salicylic acid (1f) exhibited greater efficacy against drug-resistant Candida albicans, MDR-Kb and Acinetobacter baumannii, whereas 6, 7-biphenylquinoxalin 2-sulfonamide/sulphonyl chloride (1b/1d) selectively inhibited the growth of Gram-negative bacteria. None of these compounds were active against Cryptococcus neoformans var. grubii. Furthermore, these new derivatives were tested for anthelmintic efficacy and the results indicated that new compounds had significant anthelmintic efficacy (p < 0.05) at 2.5 mg/mL, except for the salicylic acid hybrids (1f, 2f). To conclude, camphor hybrids (1a–g) demonstrated enhanced antimicrobial and anthelmintic efficacy compared to the camphor sulfonic acid hybrids (2a–g). This improved antimicrobial efficacy may be due to the increased membrane permeability of the compounds across the cell wall, via the camphor moiety, which augmented the lipophilicity of the new compounds.

A comparison of blood stream infections with extended spectrum beta-lactamase-producing and non-producing Klebsiella pneumoniae in pediatric patients

BackgroundRapid development and global spread of multidrug resistant Klebsiella pneumonia (K. pneumoniae) as a major cause of nosocomial infections is really remarkable. The aim of this study was to explore risk factors for health care associated blood stream infections (BSI) caused by ESBL-producing K. pneumoniae in children and analyze clinical outcomes.MethodsA retrospective review of patients younger than 18 years-old with blood stream infection caused by K. pneumoniae was performed. Patients with ESBL-producing K. pneumoniae isolates were compared with ESBL-non-producing isolates in terms of risk factors, outcome and mortality.ResultsAmong 111 K. pneumoniae isolates 62% (n = 69) were ESBL –producing K. pneumoniae. The median total length of hospitalization and median length of stay in hospital before infection was significantly higher in patients with ESBL-producing isolates than ESBL-non-producing. Use of combined antimicrobial treatment was significantly different between ESBL-producing and ESBL-non-producing groups, 75.4% and 24.6%, respectively (p = 0.001). Previous aminoglycoside use was higher in cases with ESBL –producing isolates (p = 0.001). Logistic regression analysis showed a significant correlation between mortality and use of combined antibiotics (OR 4.22; p = 0.01).ConclusionESBL production in K. pneumoniae isolates has a significant impact on clinical course of BSIs. Total length of hospitalization, length of hospital stay before infection, prior combined antibiotic use and use of aminoglycosides were significant risk factors for development of ESBL-producing K. pneumoniae related BSI.

In vitro characterization and inhibition of the interaction between ciprofloxacin and berberine against multidrug-resistant Klebsiella pneumoniae.

Ciprofloxacin is a quinolone antibiotic used to treat Klebsiella pneumoniae infections in the clinic. Previous studies have demonstrated that berberine exhibits antibacterial activity and less acquired resistance related to efflux pumps. The multidrug efflux pump acrAB-tolC can be stimulated to expel as much toxic material as possible from the cells, but a detrimental effect can be produced owing to an overcrowded periplasm with excess expression products, which inhibits bacterial growth. In this study, the in vitro antibacterial activities of ciprofloxacin in combination with berberine were evaluated and compared with those of ciprofloxacin and berberine alone by evaluating the MIC, MBC and summation fractional IC against 20 clinical multidrug-resistant K. pneumoniae isolates, 1 quality control bacterium and 1 induced-resistance bacterium. Susceptibility tests showed that the MIC for the combination of berberine and ciprofloxacin was 1/2 that of the individual agents or less. Antimicrobial activities of 18.18% synergy and 77.27% additivity were found. Furthermore, synergism was verified through a time-kill assay, which suggested that the synergistic antibacterial effect of the two-drug combination may, to some extent, be related to the high expression of the acrAB-tolC and acrR multidrug efflux pumps. Indeed, the expression of these genes was increased >14-fold in the isolates affected by ciprofloxacin–berberine combination synergism.

Characterization of Siphoviridae phage Z and studying its efficacy against multidrug-resistant Klebsiella pneumoniae planktonic cells and biofilm.

Biofilm has many serious consequences for public health and is a major virulence factor contributing to the chronicity of infections. The aim of the current study was to isolate and characterize a bacteriophage that inhibits multidrug-resistant Klebsiella pneumonia (M) in planktonic form as well as biofilm. This phage, designated bacteriophage Z, was isolated from wastewater. Its adsorption rate to its host bacterium was significantly enhanced by MgCl2 and CaCl2. It has a wide range of pH and heat stability. From its one-step growth, latent time and burst size were determined to be 24 min and about 320 virions per cell, respectively. As analysed by transmission electron microscopy, phage Z had an icosahedral head of width 76±10 nm, length 92±14 nm and icosahedron side 38 nm, and a non-contractile tail 200±15 nm long and 14-29 nm wide. It belongs to the family Siphoviridae in the order Caudovirales. Six structural proteins ranging from 18 to 65 kDa in size were revealed by SDS-PAGE. The genome was found to comprise double-stranded DNA with an approximate size of 36 kb. Bacteria were grown in suspension and as biofilms to compare the susceptibility of both phenotypes to the phage lytic action. Phage Z was effective in reducing biofilm biomass after 24 and 48 h, showing more than twofold and threefold reduction, respectively. Biofilm cells and stationary-phase planktonic bacteria were killed at a lower rate than exponential-phase planktonic bacteria.

Analysis of risk factors and bacterial drug resistance in severe pneumonia caused by multi-drug resistant Klebsiella pneumonia

Objective To explore the risk factors of severe pneumonia caused by multi-drug resistant Klebsiella pneumonia, and antimicrobial drug resistance among these isolates. It may help to prevent and control the disease and promote to rational use of antibiotics. Methods We conducted the case-control study in our PICU. It included 89 patients with severe pneumonia caused by multi-drug resistant Klebsiella pneumonia as case group and 68 patients with severe pneumonia caused by Klebsiella pneumonia as control group during the same period. To compare the two groups on irrationality use of antibiotics (especial for third generation cephalosporin), length of stay, tracheal cannula, time of mechanical ventilation and underlying conditions (malnutrition, congenital heart disease, heredity and metabolic disease). Antimicrobial susceptibilities among 89 multi-drug resistant Klebsiella pneumonia isolates were analyzed. Results There were 63 cases (70.79%) for irrationality use antibiotics in case group, while there were 27 cases (39.70%) in control group (P<0.01). The cases for length of stay over 7 days in case group (48 cases, 53.93%) were more than those cases with the same situation in control group (12 cases, 17.65%) (P<0.01). Thirty-eight cases (42.69%) needed mechanical ventilation therapy in case group, while 16 cases (23.53%) needed mechanical ventilation therapy in control group (P<0.01). The cases for duration of mechanical ventilation over 5 days in case group (18 cases, 20.22%) were more than those cases in control group (5 cases, 7.35%) (P<0.05). The cases with underlying disease in case group (13 cases, 14.61%) were more than those cases in control group (2 cases, 2.94%) (P<0.05). Multi-drug resistant Klebsiella pneumonia isolates demonstrated that high-level resistance for penicillins, cephalosporins, aminoglycosides and quinolones, but still susceptible to carbapenems. Conclusion Several risk factors are associated with severe pneumonia caused by multi-drug resistant Klebsiella pneumonia, including irrational use of antibiotics (especial for third generation cephalosporin), long term of length of stay, endotracheal intubation, long term of mechanical ventilation, and having underlying disease (malnutrition, congenital heart disease, heredity and metabolic disease). Multi-drug resistant Klebsiella pneumonia isolates demonstrated that high-level resistance for penicillins, cephalosporins, aminoglycosides and quinolones, but still susceptible to Carbapenems. Carbapenems should be used as first-line drugs for severe pneumonia caused by multi-drug resistant Klebsiella pneumonia. Key words: Klebsiella pneumonia; Severe pneumonia; Risk factor