Neonatal Sepsis: The Impact of Carbapenem-Resistant and Hypervirulent Klebsiella pneumoniae

The convergence of a vulnerable population and a notorious pathogen is devastating, as seen in the case of sepsis occurring during the first 28 days of life (neonatal period). Sepsis leads to mortality, particularly in low-income countries (LICs) and lower-middle-income countries (LMICs). Klebsiella pneumoniae, an opportunistic pathogen is a leading cause of neonatal sepsis. The success of K. pneumoniae as a pathogen can be attributed to its multidrug-resistance and hypervirulent-pathotype. Though the WHO still recommends ampicillin and gentamicin for the treatment of neonatal sepsis, K. pneumoniae is rapidly becoming untreatable in this susceptible population. With escalating rates of cephalosporin use in health-care settings, the increasing dependency on carbapenems, a “last resort antibiotic,” has led to the emergence of carbapenem-resistant K. pneumoniae (CRKP). CRKP is reported from around the world causing outbreaks of neonatal infections. Carbapenem resistance in CRKP is largely mediated by highly transmissible plasmid-encoded carbapenemase enzymes, including KPC, NDM, and OXA-48-like enzymes. Further, the emergence of a more invasive and highly pathogenic hypervirulent K. pneumoniae (hvKP) pathotype in the clinical context poses an additional challenge to the clinicians. The deadly package of resistance and virulence has already limited therapeutic options in neonates with a compromised defense system. Although there are reports of CRKP infections, a review on neonatal sepsis due to CRKP/ hvKP is scarce. Here, we discuss the current understanding of neonatal sepsis with a focus on the global impact of the CRKP, provide a perspective regarding the possible acquisition and transmission of the CRKP and/or hvKP in neonates, and present strategies to effectively identify and combat these organisms

Inhibition of NO2, PGE2, TNF-α, and iNOS EXpression by Shorea robusta L.: An Ethnomedicine Used for Anti-Inflammatory and Analgesic Activity

This paper is an attempt to evaluate the anti-inflammatory and analgesic activities and the possible mechanism of action of tender leaf extracts of Shorea robusta, traditionally used in ailments related to inflammation. The acetic-acid-induced writhing and tail flick tests were carried out for analgesic activity, while the anti-inflammatory activity was evaluated in carrageenan-and dextran- induced paw edema and cotton-pellet-induced granuloma model. The acetic-acid-induced vascular permeability, erythrocyte membrane stabilization, release of proinflammatory mediators (nitric oxide and prostaglandin E2), and cytokines (tumor necrosis factor-α, and interleukins-1β and -6) from lipopolysaccharide-stimulated human monocytic cell lines were assessed to understand the mechanism of action. The results revealed that both aqueous and methanol extract (400 mg/kg) caused significant reduction of writhing and tail flick, paw edema, granuloma tissue formation (P < 0.01), vascular permeability, and membrane stabilization. Interestingly, the aqueous extract at 40 μg/mL significantly inhibited the production of NO and release of PGE2, TNF-α, IL-1β, and IL-6. Chemically the extract contains flavonoids and triterpenes and toxicity study showed that the extract is safe. Thus, our study validated the scientific rationale of ethnomedicinal use of S. robusta and unveils its mechanism of action. However, chronic toxicological studies with active constituents are needed before its use

OXA-181-like carbapenemases in Klebsiella pneumoniae ST14, ST15, ST23, ST48, and ST231 from septicemic neonates: coexistence with NDM-5, resistome, transmissibility, and genome diversity

Studies on the epidemiology and genomes of isolates harboring OXA-48-like genes in septicemic neonates are rare. Here, isolates producing these carbapenemases which emerged and persisted in an Indian neonatal unit were characterized in terms of their resistome, transmissibility, and genome diversity. Antibiotic susceptibility and whole-genome sequencing were carried out. The sequence types, resistome, virulome, mobile genetic elements, and transmissibility of carbapenem-resistant plasmids were evaluated. Core genome analysis of isolates was shown in a global context with other OXA-48-like carbapenemase-harboring genomes, including those from neonatal studies. Eleven OXA-48-like carbapenemase-producing Klebsiella pneumoniae (blaOXA-181, n = 7 and blaOXA-232, n = 4) isolates belonging to diverse sequence types (ST14, ST15, ST23, ST48, and ST231) were identified. blaOXA-181/OXA-232 and blaNDM-5 were found in a high-risk clone, ST14 (n = 4). blaOXA-181/OXA-232 were in small, nonconjugative ColKP3 plasmids located on truncated Tn2013, whereas blaNDM-5 was in self-transmissible, conjugative IncFII plasmids, within truncated Tn125. Conjugal transfer of blaOXA-181/OXA-232 was observed in the presence of blaNDM-5. The study strains were diverse among themselves and showed various levels of relatedness with non-neonatal strains from different parts of the world and similarity with neonatal strains from Tanzania and Ghana when compared with a representative collection of carbapenemase-positive K. pneumoniae strains. We found that blaOXA-181/OXA-232-harboring isolates from a single neonatal unit had remarkably diverse genomes, ruling out clonal spread and emphasizing the extent of plasmid spreading across different STs. This study is probably the first to report the coexistence of blaOXA-181/232 and blaNDM-5 in neonatal isolates

KPC-2-producing Klebsiella pneumoniae ST147 in a neonatal unit: Clonal isolates with differences in colistin susceptibility attributed to AcrAB-TolC pump

This study characterizes four KPC-2-producing Klebsiella pneumoniae isolates from neonates belonging to a single sequence type 147 (ST147) in relation to carbapenem resistance and explores probable mechanisms of differential colistin resistance among the clonal cluster. Whole genome sequencing (WGS) revealed that the isolates were nearly 100% identical and harbored resistance genes (blaKPC-2,OXA-9,CTX-M-15,SHV-11,OXA-1,TEM-1B, oqxA, oqxB, qnrB1, fosA, arr-2, sul1, aacA4, aac(6′)Ib-cr, aac(6′)Ib), and several virulence genes. blaKPC-2 was the only carbapenem-resistant gene found, bracketed between ISKpn7 and ISKpn6 of Tn4401b on a non-conjugative IncFII plasmid. Remarkably, one of the clonal isolates was resistant to colistin, the mechanistic basis of which was not apparent from comparative genomics. The transmissible colistin resistance gene, mcr, was absent. Efflux pump inhibitor, carbonyl cyanide 3-chlorophenylhydrazone (CCCP) rendered a 32-fold decrease in the minimum inhibitory concentration (MIC) of colistin in the resistant isolate only. acrB, tolC, ramA, and soxS genes of the AcrAB-TolC pump system overexpressed exclusively in the colistin-resistant isolate, although the corresponding homologs of the AcrAB-TolC pump, regulators and promoters were mutually identical. No change was observed in the expression of other efflux genes (kpnE/F and kpnG/H) or two-component system (TCS) genes (phoP/phoQ, pmrA/pmrB). Colistin resistance in one of the clonal KPC-2-producing isolates is postulated to be due to overexpression of the AcrAB-TolC pump. This study is probably the first to report clinical clonal K. pneumoniae isolates with differences in colistin susceptibility. The presence of carbapenem-resistant isolates with differential behavior in the expression of a genomically identical pump system indicates the nuances of the resistance mechanisms and the difficulty of treatment thereof

Carriage and within-host diversity of mcr-1.1-harboring Escherichia coli from pregnant mothers: inter- and intra-mother transmission dynamics of mcr-1.1

Exchange of antimicrobial resistance genes via mobile genetic elements occur in the gut which can be transferred from mother to neonate during birth. This study is the first to analyze transmissible colistin resistance gene, mcr, in pregnant mothers and neonates. Samples were collected from pregnant mothers (rectal) and septicaemic neonates (rectal & blood) and analyzed for presence of mcr, its transmissibility, genome diversity, and exchange of mcr between isolates within an individualand across different individuals (not necessarily mother-baby pairs). mcr-1.1 was detected in rectal samples of pregnant mothers (n=10, 0.9%), but not in neonates. All mcr-positive mothers gave birth to healthy neonates from whom rectal specimen were not collected. Hence, transmission of mcr between these mother-neonate pairs could not be studied. mcr-1.1 was noted only in Escherichia coli (phylogroup A & B1), and carried few resistance and virulence genes. Isolates belonged to diverse sequence types (n=11) with two novel STs (ST12452, ST12455). mcr-1.1 was borne on conjugative IncHI2 bracketed between ISApl1 on Tn6630, and the plasmids exhibited similarities in sequences across the study isolates. Phylogenetic comparison showed that study isolates were related to mcr-positive isolates of animal origin from Southeast Asian countries. Spread of mcr-1.1 within this study occurred either via similar mcr-positive clones or similar mcr-bearing plasmids in mothers. Though this study could not build evidence for mother-baby transmission, but presence of such genes in the maternal specimen may enhance the chances of transmission to neonates

Development and evaluation of a PCR assay for rapid detection of azithromycin resistant Campylobacter isolated from diarrhoeal patients in Kolkata, India

Abstract Background Campylobacter is a well-known bacterial pathogen for triggering acute gastroenteritis in humans both in developed and developing countries. This organism is highly resistant to fluoroquinolones. Macrolides are very much useful for the treatment of campylobacteriosis when clinical therapy is necessary. However, increasing resistance to azithromycin, a potent macrolide has been reported in Campylobacter in recent years. Macrolide resistance in Campylobacter is found mainly due to point mutation in V region of 23S rRNA. Results We have developed a PCR based assay, which can detect the azithromycin resistant and sensitive Campylobacter strains utilizing mutation responsible for the phenotype. This PCR was validated using 359 Campylobacter strains isolated from diarrhoeal patients at Kolkata, India. Antimicrobial resistance through disk diffusion method was also performed on these strains as a gold standard. Studies through sequencing analysis further confirmed the PCR result. Conclusion This study describes a simple and rapid method for detection of mutation conferring macrolide resistance with additional feature of identification of sensitive strains

Ternary iron(II) complex with an emissive imidazopyridine arm from schiff base cyclizations and its oxidative DNA cleavage activity

The ternary iron(II) complex [Fe(L')(L")](PF6)3( 1) as a synthetic model for the bleomycins, where L' and L" are formed from metal-mediated cyclizations of N,N'-(2-hydroxypropane-1,3-diyl)bis(pyridine-2-aldimine)(L), is synthesized and structurally characterized by X-ray crystallography. In the six-coordinate iron(II) complex, ligands L' and L" show tetradentate and bidentate chelating modes of bonding. Ligand L is formed from an intramolecular attack of the alcoholic OH group of L to one imine moiety leading to the formation of a stereochemically constrained five-membered ring. Ligand L" which is formed from an intermolecular reaction involving one imine moiety of L and pyridine-2-carbaldehyde has an emissive cationic imidazopyridine pendant arm. The complex binds to double-stranded DNA in the minor groove giving a Kapp value of 4.1 &#215; 105 M-1 and displays oxidative cleavage of supercoiled DNA in the presence of H2O2 following a hydroxyl radical pathway. The complex also shows photo-induced DNA cleavage activity on UV light exposure involving formation of singlet oxygen as the reactive species

Dalton Ternary iron(II) complex with an emissive imidazopyridine arm from Schiff base cyclizations and its oxidative DNA cleavage activity †

The ternary iron(II) complex [Fe(L )(L )](PF 6

Ternary iron(II) complex with an emissive imidazopyridine arm from Schiff base cyclizations and its oxidative DNA cleavage activity

The ternary iron(II) complex [Fe(L')(L")] $(PF_6)_3(1)$ as a synthetic model for the bleomycins, where L' and L" are formed from metal-mediated cyclizations of N,N -(2-hydroxypropane-1,3-diyl)bis(pyridine-2-aldimine)(L), is synthesized and structurally characterized by X-ray crystallography. In the six-coordinate iron(II) complex, ligands L' and L" show tetradentate and bidentate chelating modes of bonding. Ligand L' is formed from an intramolecular attack of the alcoholic OH group of L to one imine moiety leading to the formation of a stereochemically constrained five-membered ring. Ligand L" which is formed from an intermolecular reaction involving one imine moiety of L and pyridine-2-carbaldehyde has an emissive cationic imidazopyridine pendant arm. The complex binds to double-stranded DNA in the minor groove giving a K_a_p_p value of 4.1 x $10^5 M^�^1$ and displays oxidative cleavage of supercoiled DNA in the presence of $H_2O_2$ following a hydroxyl radical pathway. The complex also shows photo-induced DNA cleavage activity on UV light exposure involving formation of singlet oxygen as the reactive species

Evaluation of co-transfer of plasmid-mediated fluoroquinolone resistance genes and bla NDM gene in Enterobacteriaceae causing neonatal septicaemia

Abstract Background The bla NDM-1 (New Delhi Metallo-β-lactamase-1) gene has disseminated around the globe. NDM-1 producers are found to co-harbour resistance genes against many antimicrobials, including fluoroquinolones. The spread of large plasmids, carrying both bla NDM and plasmid-mediated fluoroquinolone resistance (PMQR) markers, is one of the main reasons for the failure of these essential antimicrobials. Methods Enterobacteriaceae (n = 73) isolated from the blood of septicaemic neonates, admitted at a neonatal intensive care unit (NICU) in Kolkata, India, were identified followed by PFGE, antibiotic susceptibility testing and determination of MIC values for meropenem and ciprofloxacin. Metallo-β-lactamases and PMQRs were identified by PCR. NDM-positive isolates were studied for mutations in GyrA & ParC and for co-transmission of bla NDM and PMQR genes (aac(6′)-Ib-cr, qnrB, qnrS) through conjugation or transformation. Plasmid types, integrons, plasmid addiction systems, and genetic environment of the bla NDM gene in NDM-positive isolates and their transconjugants/ transformants were studied. Results Isolated Enterobacteriaceae comprised of Klebsiella pneumoniae (n = 55), Escherichia coli (n = 16), Enterobacter cloacae (n = 1) and Enterobacter aerogenes (n = 1). The rates of ciprofloxacin (90%) and meropenem (49%) non-susceptibility were high. NDM was the only metallo-β-lactamase found in this study. NDM-1 was the predominant metallo-β-lactamase but NDM-5, NDM-7, and NDM-15 were also found. There was no significant difference in ciprofloxacin non-susceptibility (97% vs 85%) and the prevalence of PMQRs (85% vs 77%) between NDM-positive and NDM-negative isolates. Among the PMQRs, aac(6′)-Ib-cr was predominant followed by qnrB1 and qnrS1. Twenty-nine isolates (40%) co-harboured PMQRs and bla NDM, of which 12 co-transferred PMQRs along with bla NDM in large plasmids of IncFIIK, IncA/C, and IncN types. Eighty-two percent of NDM-positive isolates possessed GyrA and/or ParC mutations. Plasmids carrying only bla NDM were of IncHIB-M type predominantly. Most of the isolates had ISAba125 in the upstream region of the bla NDM gene. Conclusion We hypothesize that the spread of PMQRs was independent of the spread of NDM-1 as their co-transfer was confirmed only in a few isolates. However, the co-occurrence of these genes poses a great threat to the treatment of neonates