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In vitro susceptibility testing of aztreonam-avibactam against predominantly NDM-producing Enterobacterales in Peru.

Metallo-β-lactamase-producing Enterobacterales are distributed worldwide, but some Latin American countries show a higher prevalence. Aztreonam-avibactam (ATM-AVI) may be an option for treating these infections. To evaluate in vitro susceptibility to aztreonam (ATM) alone and ATM-AVI in carbapenem-non-susceptible Enterobacterales isolates, based on the type of carbapenemase production, we prospectively collected carbapenem-non-susceptible Enterobacterales isolates from Peruvian hospitals during 2023-2024. Identification and susceptibility testing were performed by commercial panels and disk diffusion. Carbapenemases were detected by immunochromatography. ATM and ATM-AVI MICs were determined using broth microdilution panels with avibactam fixed at 4 µg/mL. The non-susceptible isolates to ATM-AVI and those with double production of carbapenemases underwent whole-genome sequencing. A total of 438 Enterobacterales isolates were analyzed; carbapenemase production was detected in 422 (96.3%) and NDM was the most frequent (61.9%). Coproduction of NDM + KPC in K. pneumoniae and NDM + OXA-48-like in Escherichia coli was observed. Overall, 99.3% were susceptible to ATM-AVI; MIC50 and MIC90 were 0.12 and 2 µg/mL, respectively. Overall, K. pneumoniae isolates had lower MIC50 and MIC90 values to ATM-AVI (0.12 and 0.5 µg/mL) compared to E. coli (0.5 and 4 µg/mL). Three E. coli isolates were resistant to ATM-AVI (MIC ≥ 8 µg/mL), they belonged to ST410, ST167, and ST10 and harbored a YRIN insertion in PBP3 along with CYM-type, PER-type, and CTX-M-type beta-lactamase genes. ATM-AVI demonstrated potent activity against carbapenem-non-susceptible Enterobacterales, including those producing NDM, which is the carbapenemase most frequently detected in Peruvian hospitals.IMPORTANCEEnterobacterales isolates cause common illnesses in humans. Carbapenems are the antibiotics used to treat several of these infections, and increasingly, isolates resistant to these antibiotics are found. The most important mechanism of resistance to carbapenem among Enterobacterales is the production of enzymes called carbapenemases. Our results allowed us to recognize that NDM is the most frequent type of carbapenemase detected. Most of the antimicrobials available do not cover the Enterobacterales carrying NDM carbapenemase. In this scenario, we found that the new combination of drugs, aztreonam-avibactam, has high in vitro efficacy against most of the carbapenem-resistant isolates and against those isolates carrying NDM carbapenemase.

Aztreonam

Outbreak of aztreonam-avibactam-resistant NDM-5-producing Escherichia coli isolates in a hospital of Paris.

The emergence of aztreonam-avibactam resistance among NDM-producing Escherichia coli represents a major therapeutic and infection control concern. Four cases of aztreonam-avibactam-resistant (AZAR) NDM-producing E. coli, recovered from three blood cultures and one rectal surveillance culture in a hospital of Paris, prompted an investigation based on whole-genome sequencing. The three isolates responsible for bloodstream infection, which were clonally related, belonged to the ST405 and produced NDM-5, DHA-1, CTX-M-15, and TEM-1 β-lactamases. They also had a penicillin-binding protein 3 (PBP3) modified by the insertion of four amino acids (YRIK). On the other hand, the isolate recovered from the rectal swab belonged to another sequence type (ST2083). It produced NDM-5, CMY-42, and TEM-1 β-lactamases and had an altered PBP3 by the insertion of four other residues (YRIN). Epidemiological investigation identified endoscopic retrograde cholangiopancreatography as a potential risk factor, leading to the detection of three additional patients infected with the ST405 clone after exposure to the same duodenoscope. The outcome of the bloodstream infections was favorable except for one patient. In total, seven patients infected or colonized by AZAR NDM-5-producing E. coli were identified over a 5-month period in 2025, six with duodenoscope exposure.IMPORTANCEThis study underlines the emergence of aztreonam-avibactam resistance among NDM-producing Escherichia coli isolates in France. To our knowledge, this report describes the first clonal outbreak due to aztreonam-avibactam-resistant NDM-producing E. coli.

Humans

Genomic and functional characterization of ST11-KL64 hypervirulence-associated carbapenem-resistant Klebsiella pneumoniae co-harboring bla KPC-2 and bla NDM-13.

BACKGROUND: Hypervirulence-associated carbapenem-resistant Klebsiella pneumoniae (hv-CRKP) is a major clinical and public health threat. However, ST11-KL64 hv-CRKP co-harboring bla KPC-2 and bla NDM-13 remains poorly characterized, particularly regarding genomic relatedness, plasmid dynamics, and attenuated virulence-associated phenotypes. METHODS: We retrospectively investigated clinical K. pneumoniae isolates collected at a tertiary hospital in Chengdu, China, between January and December 2024. Hypervirulence-associated markers were screened by PCR, followed by antimicrobial susceptibility testing and carbapenemase inhibitor enhancement assay to identify genotype-defined hv-CRKP. All isolates were subjected to molecular typing. ST11-KL64 isolates co-harboring bla KPC-2 and bla NDM-13 were subjected to Illumina sequencing, with the representative isolate K3 undergoing hybrid whole-genome sequencing and functional characterization. RESULTS: Among the 46 hvKP isolates recovered from 43 patients, 35 were identified as hv-CRKP, predominantly ST11-KL64. Three ST11-KL64 hv-CRKP isolates co-harbored bla KPC-2/bla NDM-13, and Illumina sequencing coupled with core-genome SNP (cgSNP) typing revealed minimal genetic variation. The expanded cgSNP analysis supported close relatedness between K3 and Beijing isolate K56649. K3 carried a pLVPK-like virulence plasmid, a bla KPC-2-bearing IncFII/IncR plasmid, and a bla NDM-13-bearing IncI1 plasmid. Relative to pK2044, K3 exhibited an rmpA-proximal ISKpn26-associated insertion and a complex alteration of the 5'-terminal coding region of rmpA. The bla NDM-13 plasmid was conjugatively transferred to Escherichia coli C600 with a mean conjugation frequency of 5.213 × 10-3 transconjugants per recipient cell and bla NDM-13 maintained high stability following approximately 100 generations of antibiotic-free passage, whereas bla KPC-2 was not detected under the tested conditions. Phenotypically, K3 showed a negative string test, low mucoviscosity, and attenuated virulence-associated phenotypes. CONCLUSION: Our results reveal that the three isolates formed a closely related local genomic cluster, among which K3 was closely related to the K56649 clone. In addition, K3 exhibited conjugative transfer capacity of the bla NDM-13-bearing IncI1 plasmid, and alterations at the rmpA locus accompanied by reduced rmpA transcript abundance were associated with low mucoviscosity.

IncI1 plasmid

Extensive pneumocephalus in a fatal central nervous system infection caused by NDM-1-producing carbapenem-resistant Klebsiella pneumoniae: a case report.

BACKGROUND: Central nervous system (CNS) infections caused by New Delhi metallo-β-lactamase-1 (NDM-1)-producing carbapenem-resistant Klebsiella pneumoniae (CRKP) are rare but associated with extremely high mortality because of extensive antimicrobial resistance and poor blood-brain barrier (BBB) penetration. To the best of our knowledge, there have been no published reports of pneumocephalus associated with infection caused by NDM-1-producing K. pneumoniae. CASE PRESENTATION: We report an 18-year-old woman who developed bloodstream infection and metastatic CNS infection following severe thoracoabdominal crush injury. Serial cerebrospinal fluid (CSF) cultures repeatedly yielded NDM-1-producing CRKP despite multiple adjustments of antimicrobial therapy. Retrospective whole-genome sequencing demonstrated that blood and CSF isolates belonged to the same clonal lineage carrying the blaNDM-1 gene on an IncX3 plasmid, confirming hematogenous dissemination. Serial cranial computed tomography revealed progressive diffuse cerebral edema and extensive pneumocephalus in the absence of skull fracture or neurosurgical intervention. Persistent microbiological failure was mainly attributed to the combination of NDM-1-mediated multidrug resistance and inadequate CNS antibiotic exposure, which ultimately led to the patient's death. CONCLUSION: This case illustrates the devastating clinical course of NDM-1-producing CRKP CNS infection and identifies extensive pneumocephalus as a rare but potentially fatal complication. It emphasizes the importance of early molecular diagnosis, repeated CSF microbiological assessment, optimization of antimicrobial regimens with adequate CNS penetration, and implementation of effective infection-control strategies. The case also highlights the urgent need for novel therapeutic approaches against metallo-β-lactamase-producing pathogens.

blaNDM-1 gene

FTIR typing of the emerging NDM-14-producing Klebsiella pneumoniae ST147 clone.

UNLABELLED: The emergence and rapid dissemination of NDM-14-producing Klebsiella pneumoniae ST147 represents a major challenge for infection control, requiring timely and reliable outbreak detection tools. In this study, we evaluated Fourier-transform infrared (FTIR) spectroscopy as a rapid typing method for outbreak investigation and compared its performance with whole-genome sequencing (WGS). A collection of 64 carbapenemase-producing K. pneumoniae isolates, including 30 NDM-14-producing ST147 isolates associated with a regional outbreak in the Canary Islands, was analyzed using FTIR spectroscopy and WGS. FTIR-based clustering was optimized using the polysaccharide spectral region and a customized distance cutoff. Genomic relatedness was assessed using multilocus sequence typing, core-genome single-nucleotide polymorphism (SNP) analysis at multiple thresholds, and clustering agreement indices. FTIR identified a dominant spectral cluster comprising 31 isolates, capturing all outbreak-related isolates with 100% sensitivity and 97% specificity. FTIR clustering showed concordance with genomic outbreak definitions at stringent SNP thresholds (10-18 SNPs), with accuracy exceeding 98%. Pairwise distance analysis revealed low FTIR dissimilarity among closely related isolates, whereas increased dispersion occurred at intermediate genomic distances (15-30 SNPs). Agreement indices showed improved concordance as genomic stringency increased, with the Modified Adjusted Rand Index values reaching 94.75 at the 10-SNP threshold. Importantly, FTIR identified an NDM-14-producing isolate from a distinct clonal background. Overall, FTIR spectroscopy provides a rapid and reliable first-line screening tool for identifying homogeneous outbreak clusters. However, due to lineage-dependent behavior and limited resolution at intermediate genomic distances, WGS remains essential for confirmatory analysis and precise delineation of transmission events. IMPORTANCE: The rapid spread of multidrug-resistant Klebsiella pneumoniae poses a major challenge for infection control, particularly during hospital outbreaks where timely identification of transmission is essential. In this study, we evaluate Fourier-transform infrared (FTIR) spectroscopy as a rapid typing approach and compare its performance with whole-genome sequencing in the context of an outbreak caused by NDM-14-producing K. pneumoniae ST147. Our results show that FTIR can reliably identify highly related isolates within a clonal outbreak, supporting early outbreak recognition. However, its performance is influenced by the underlying genomic structure of the population and may require dataset-specific optimization. These findings highlight the potential of FTIR as a first-line screening tool while emphasizing the need for cautious interpretation and integration with genomic methods for accurate outbreak delineation.

Klebsiella pneumoniae

Genomic characterization of KPC-2 and NDM coproducing carbapenem-resistant Klebsiella pneumoniae in a hospital: discovery of ST1869 clone and a novel hybrid plasmid.

UNLABELLED: To characterize the plasmid architecture and molecular background of KPC-NDM coproducing carbapenem-resistant Klebsiella pneumoniae (KN-CRKP) in a South China hospital. Five KN-CRKP isolates were collected, including three from one patient. All underwent Illumina sequencing; two (ST11 and ST1869) additionally had Nanopore sequencing. Antimicrobial susceptibility testing strain sequence types, conjugation assays, resistance gene profiling, plasmid typing, genetic structure comparison, core-genome single nucleotide polymorphisms (SNPs) analysis, and plasmid clustering were performed. All isolates exhibited an imipenem minimum inhibitory concentration (MIC) of ≥128 µg/mL and harbored multiple resistance genes. One isolate (1/5) belonged to ST1869 and co-harbored blaKPC-2 and blaNDM-5. The blaNDM-5-carrying plasmid was a novel IncI1/X3 fusion plasmid that also carried blaCMY-42. Unlike several IncX3 plasmids carrying blaNDM in publicly available KN-CRKP genomes from South China, this IncI1/X3 hybrid lacked a complete conjugative transfer system. ST11 was the predominant clone (4/5), co-harboring blaKPC-2 and blaNDM-1. A rare genetic structure, ΔISKpn6-blaKPC-2-ISKpn28, was identified on IncFII plasmids carrying blaKPC-2. Plasmid clustering analysis of 126 comparative KN-CRKP genomes showed diverse sequence types and plasmid backgrounds associated with the KPC/NDM co-production pattern. The observed plasmid diversity and structural variation in KN-CRKP support continued genomic surveillance, with particular attention to the ST1869 clone, the novel IncI1/X3 hybrid plasmid harboring blaNDM-5 and blaCMY-42, and the rare "ΔISKpn6-blaKPC-2-ISKpn28" genetic structure. Expanded genomic data on KN-CRKP are needed to further elucidate its resistance mechanisms and plasmid evolutionary trajectories. IMPORTANCE: The co-production of KPC and NDM carbapenemases in Klebsiella pneumoniae poses a formidable threat to clinical antimicrobial therapy, as these enzymes confer resistance to virtually all β-lactam agents, including carbapenems. Here, we report novel genomic features of KN-CRKP in South China, including the emergence of the ST1869 clone, a unique IncI1/X3 hybrid plasmid harboring blaNDM-5 and blaCMY-42, and the rare ΔISKpn6-blaKPC-2-ISKpn28 genetic structure. These findings substantially expand current understanding of plasmid evolution and resistance gene dissemination in this region. The identification of diverse resistance mechanisms and clonal backgrounds supports enhanced genomic surveillance and infection-control awareness for pan-resistant Enterobacterales.

Plasmids

Characteristics of an NDM-1-producing Klebsiella pneumoniae strain belonging to ST105.

Uncommon multilocus sequence types (MLSTs) of NDM-producing Klebsiella pneumoniae may pose a significant threat to patients, although they are often overlooked in surveillance studies. Characterizing these isolates is therefore important for infection control. In this study, the antimicrobial susceptibility and pathogenicity of K. pneumoniae strain KP_WXD, pertaining to the atypical sequence type ST105, were evaluated, including capsular polysaccharide (CPS) production, biofilm formation, and resistance to serum killing. Whole-genome sequencing (WGS) was performed to analyze its genomic features. K. pneumoniae KP_WXD strain was resistant to all tested β-lactam agents. Its virulence was lower than that of K. pneumoniae strains ST11-KL64 and NTUH-k2044 used as references, while its biofilm formation ability was stronger than that of both strains. WGS analysis revealed carriage of IncF and IncN plasmids carrying multiple antibiotic resistance genes, alongside blaNDM-1 and blaCTX-M, integrated into well-characterized mobile genetic elements. Moreover, both blaNDM-1 and blaCTX-M-harboring plasmids were transferable to E. coli J53 by conjugation without significant fitness cost on the recipient strain.

Klebsiella pneumoniae

Characterisation of Carbapenem-Resistant Raoultella planticola and Structural Analysis of NDM Composite Plasmids.

OBJECTIVE: This study aimed to investigate the molecular characteristics, resistant plasmid structures and phylogeny of a carbapenem-resistant Raoultella planticola (CRRP) strain from a patient with pneumonia to inform antimicrobial resistance control strategies. METHODS: We performed strain identification using MALDI-TOF MS, the BD Phoenix 100 system and whole-genome sequencing (WGS). We assessed antimicrobial susceptibility and resistance gene transfer using PCR, conjugation and stability assays, plasmid structure using a bioinformatics tool and phylogeny using a core-genome phylogenetic tree. RESULTS: WGS confirmed the isolate as R. planticola (average nucleotide identity (ANI) > 98.9% with reference type strains), co-harbouring blaKPC-2 and blaNDM-1. It was resistant to 19 antimicrobial agents and susceptible to only polymyxin, amikacin and chloramphenicol. Resistance genes were present on two conjugative plasmids: pzwx_KPC (IncFIA) and pzwx_NDM (a novel repFIB/repHI5B hybrid assembled via non-homologous end joining). Both plasmids demonstrated efficient transfer and stable inheritance over 12 passages. pzwx_KPC was highly homologous to plasmids from Klebsiella pneumoniae. Phylogenetic analysis revealed the closest relationship with German R. planticola strains. CONCLUSION: CRRP carries highly transmissible and stable resistance plasmids. Strengthened monitoring in immunocompromised patients and improved environmental disinfection are recommended. The risk of misidentification by automated systems underscores the importance of WGS for accurate pathogen identification.

Carbapenem resistance

Gene transfer from NDM-5-producing and OXA-48-producing Enterobacter hormaechei ST79 on contaminated dicloxacillin capsules to other Enterobacterales in Europe, 2020-23: a retrospective, observational, molecular epidemiological study.

BACKGROUND: In February, 2023, an outbreak of Enterobacter hormaechei ST79 carrying blaNDM-5 and blaOXA-48 was linked to contaminated dicloxacillin capsules administered to approximately 79 000 individuals in Denmark. Initial clonal outbreak investigations identified 11 patients with the E hormaechei ST79 outbreak strain, which carried blaNDM-5 on a distinct IncX3 plasmid, and in nine cases, blaOXA-48 was on a distinct IncL plasmid. Interspecies plasmid transfer was observed in one patient, suggesting a potential plasmid-mediated outbreak involving other Enterobacterales. However, no studies have characterised the progression of a clonal outbreak originating from a contaminated medicine into plasmid-mediated dissemination of carbapenemase genes. Hence, we aimed to characterise the clonal and plasmid-mediated spread of carbapenemase genes in this outbreak. METHODS: We conducted a retrospective genomic and epidemiological investigation using existing short-read whole-genome sequencing data from all carbapenemase-producing Enterobacterales (CPE) from the Danish national surveillance, collected between Jan 1, 2014, and Oct 1, 2023. All confirmed CPE isolates were eligible for inclusion. Using in-silico screening for unique fragments of the two outbreak plasmids, we selected 160 isolates for long-read sequencing to obtain complete plasmid sequences for outbreak investigation. Analyses were descriptive and included comparison of sequence identity and coverage to define outbreak-associated plasmids and summary statistics of patient characteristics. FINDINGS: Data from 1829 isolates were obtained. We detected 16 of 53 isolates involved in the outbreak using conventional outbreak detection methods. The remaining 37 isolates were detected using plasmid-specific screening and long-read sequencing. 15 patients carried the outbreak E hormaechei strain, including the 11 patients previously reported. Three of the 15 patients presented with at least one additional bacterial species carrying one or both outbreak plasmids (pDcap_OXA-48 and pDcap_NDM-5). A further 24 patients, sampled between July 1, 2020, and Oct 1, 2023, presented with other Enterobacterales carrying one or both outbreak-associated plasmids but not the original E hormaechei ST79 strain. In four cases, outbreak-associated plasmids differed structurally from the original outbreak plasmid. INTERPRETATION: This study describes how a clonal CPE outbreak caused by a contaminated medicine evolved into a complex plasmid-mediated outbreak involving multiple Enterobacterales species. Most patients related to the outbreak did not present with the original E hormaechei ST79 outbreak strain and were therefore not identified using standard outbreak detection methods. These findings highlight the importance of using plasmid-focused approaches in outbreak investigations. FUNDING: The Danish Ministry of Health, SSI-Seq (cofunded by EU4Health).

Humans

New Delhi metallo-β-lactamase-producing Acinetobacter baumannii in the USA from October, 2013, to March, 2022: a retrospective molecular epidemiological analysis.

BACKGROUND: Most US carbapenem-resistant Acinetobacter baumannii (CRAB) isolates harbour carbapenem-hydrolysing class D β-lactamases. Other carbapenemases, such as New Delhi metallo-β-lactamase (NDM), are uncommon but emerging. We describe the epidemiology of NDM-producing CRAB reported to the US Centers for Disease Control and Prevention (CDC). METHODS: We defined cases as A baumannii with blaNDM confirmed by molecular testing and isolated from any specimen source from a patient in the USA between Oct 1, 2013, and March 31, 2022, and passively reported to the CDC from regional, state, local public health, and CDC laboratories. Epidemiologically linked cases had epidemiological linkage (eg, overlapping health-care facility stay) with one or more other cases. We assessed case relatedness through analysis of whole-genome sequence data using traditional multilocus sequence typing (MLST; Oxford scheme [sequence typeOX]) and core genome MLST. To understand the potential origins of NDM-CRAB in the USA, we compared sequences of cases to US CRAB without NDM and to NDM-CRAB from non-US locations. FINDINGS: We identified 327 NDM-CRAB cases from 264 patients in 21 US states. Among patients with available epidemiological information, 192 (90%) of 214 had epidemiological linkage to at least one additional case and 13 (7%) of 193 were hospitalised outside the USA 12 months or less before index specimen collection. Five regionally distinct sequence type clusters were identified among the 264 case patients; three (sequence type OX218, sequence type OX281, and sequence type OX1697) were closely related to international NDM-CRAB isolates. INTERPRETATION: We identified regionally distinct NDM-CRAB strains, suggesting localised transmission in the USA. Some NDM-CRAB strains in the USA are closely related to strains identified outside the USA, suggesting that spread followed importation. FUNDING: None.

Acinetobacter baumannii

Lipid status after combined pancreas-kidney transplantation and kidney transplantation alone in type I diabetes mellitus.

This study was designed to compare changes in lipid status following organ transplantation between type I diabetes mellitus (DM-I) patients receiving combined pancreas-kidney transplantation (PKT) with those receiving kidney transplantation alone (KTA). A retrospective chart review was used to identify pre- and posttransplantation fasting total cholesterol (TC) and triglycerides (TG) in three groups: DM-I patients receiving KTA (DM:KTA; n = 14), DM-I patients receiving PKT (DM:PKT; n = 20), and kidney transplant recipients without DM (NDM; n = 16). The groups were matched for age, gender, weight, duration of dialysis, smoking history, and duration of diabetes mellitus. Linear regression was used to analyze differences in lipid trends over time (up to 24 months posttransplantation) and the effects of prednisone dose, cyclosporine dose, and serum creatinine. Preoperative TC was significantly lower in the DM:KTA group (P < 0.05) compared with DM:PKT or NDM. There were no significant differences in preoperative TG between the three groups. TC and TG decreased over time only in DM:PKT (P = 0.0112, P = 0.0278, respectively). TC increased and TG was unchanged over time in DM:KTA (P = 0.0003, P = 0.1103, respectively). Neither TC nor TG changed over time in NDM. Trends of TC and TG for DM:PKT were significantly different from DM:KTA (P < 0.01 for both). Trend of TC for NDM was also significantly different from DM:PKT (P = 0.0061). Prednisone dose was significantly related to TC in DM:KTA and NDM (P < 0.01) while cyclosporine dose was significantly related to TC for DM:KTA only (P = 0.0013) in the presence of time. None of the variables tested (prednisone dose, cyclosporine dose, and serum creatinine) significantly affected TG in the presence of time. In summary, TC and TG decreased over time only in DM:PKT. In contrast, TC increased while TG was unchanged in DM:KTA over the same interval (0-24 months). If these trends continue, the beneficial change in lipids in the DM:PKT group may translate into a net improvement in atherosclerosis-mediated events for diabetic patients with chronic renal failure who receive PKT compared with those who do not.

Adult

Renal transplantations from the same kidney donor: outcome of diabetic and non-diabetic patients.

Diabetic (DM) nephropathy is an indication of renal transplantation in 30% of all cases in our hospital. We assessed retrospectively the outcome of these diabetics (DM) in comparison with their non-diabetic (NDM) controls. Each diabetic (n = 24) had a control (n = 24) receiving a kidney from the same donor. There was no difference in the stage of uraemia preoperatively. Anaesthesia and fluid therapy were standardized. Peroperative hypotension occurred more often in diabetics (NS). All operating parameters including cold ischaemia were comparable. Kidney function started immediately in 14/24 in the DM group and 13/24 in the NDM group and was delayed in 10/24 and 11/24, respectively. One diabetic patient rejected the transplant as did two non-diabetic patients. Postoperatively diuretics could be discontinued more often in the DM than in the NDM group (p < 0.05). Antihypertensives had to be started in the NDM more often (NS) than in the DM group. In conclusion, the outcome of diabetic patients after renal transplantation was comparable to their NDM controls.

Adult

Deciphering the genomic landscape of novel Acinetobacter non-baumannii lineages causing neonatal septicemia: carbapenem resistance and virulence.

BACKGROUND: Acinetobacter non-baumannii (Anb) species are reported worldwide to cause infections in both adults and neonates, although less frequently than Acinetobacter baumannii. However, limited information is available on their genomic diversity, resistance mechanisms, and virulence potential. This study investigates novel Anb isolates causing neonatal septicemia in India to characterize their resistance and pathogenic traits. METHODS: Anb isolates from neonatal blood cultures (2007-2025) were identified by VITEK2 Compact system, MALDI-TOF MS, and Whole-genome sequencing (WGS). Antimicrobial susceptibility was tested by VITEK2. Genomic analysis included MLST, resistome, virulome, plasmid typing, integrons, and core-genome phylogeny analysis. In vitro and in vivo studies assessed pathogenic potential of Anb species. RESULTS: Anb infections were low (11%) among the neonates during the study period. WGS revealed 11 novel Sequence Types (STs) which include A. indicus, A. variabilis, A. schindleri, and A. bereziniae. Six out of these eleven Anbs harbored carbapenemases such as bla NDM-1 and/or bla OXA-58-like genes (bla OXA-58, bla OXA-420). bla NDM-1 was acquired via Tn125 transposon. ISAba125 was located upstream of bla NDM-1, and a conserved structure extending to IS91 family transposase was detected in bla NDM-1-harboring genomes. bla OXA-58-like genes were found to be associated with ISAba3. Most carbapenemases were likely located on chromosome. Class 1 integrons carrying multiple antimicrobial resistance genes (ARGs) and diverse plasmid replicase families were detected in Anbs. Core genome phylogeny showed that the study Anbs were not closely related to the global Anbs. In vitro virulence-associated assays (biofilm formation, surface motility, adherence/invasion, apoptosis) and in vivo lethality in murine infection model showed reduced pathogenicity, reinforcing earlier observations that Anb species are generally less virulent than A. baumannii. Several virulence factors (VFs) were detected; however, no clear correlation was observed between virulence genes, in vitro pathogenicity, and in vivo lethality. CONCLUSION: These results indicate the multifactorial nature of Anb pathogenicity and the current limitations of knowledge of its VFs. However, the presence of numerous VFs suggests a capacity to cause disease, particularly in vulnerable host populations such as neonates. Furthermore, the presence of multiple ARGs indicates a strong potential for persistence and dissemination in hospital environments with high antibiotic pressure. Overall, these findings underscore the importance of continued AMR surveillance, genome characterization and further investigations into Anb pathogenicity.

Acinetobacter non-baumannii

A neuromagnetic study of selective auditory attention.

Auditory event-related magnetic fields and electrical potentials were recorded from subjects who were instructed to attend to a sequence of constant pitch tones presented to one ear and ignore a concurrent sequence of tones with a different pitch presented to the other ear. Subjects' task was to detect and count longer duration 'target' tones (P = 0.1) interspersed with 'standard' tones (P = 0.4) in the attended ear and to ignore tones (both standards and targets) in the other ear. All stimuli, both attended and ignored, elicited a prominent response approximately 100 msec after tone onset (N1m). Beginning approximately 150 msec following stimulus onset, an attention-dependent modulation of the magnetic response (Ndm) was observed for each subject. In 2 subjects whose magnetic field patterns were mapped in detail, equivalent current dipole (ECD) modeling was used to estimate the sources of N1m and Ndm activity. By transforming the coordinate systems for magnetic resonance images (MRIs) and ECD solutions, the locations and orientations of ECDs were determined relative to each subject's brain structures. ECDs for both N1m and Ndm were located in auditory cortex along the posterior regions of the sylvian fissure. Monte Carlo error analyses indicated that the ECD for Ndm is near, but significantly anterior to that for N1m.

Adult

Prevention of surface-to-human transmission of rotaviruses by treatment with disinfectant spray.

A model was developed to examine the effects of disinfectants on the transmission of infectious rotavirus from a dried surface to humans. The initial experiments were designed to find a method of preserving rotavirus infectivity during drying. Culture-adapted human rotavirus (CJN strain) was dried at room temperature in different organic suspensions, including fecal matter, several laboratory media, and nonfat dry milk (NDM). Recoveries of infectious virus were then compared. Fecal matter provided little protection in this study relative to distilled water, but the other suspensions were quite protective, especially NDM, which consistently allowed recoveries of greater than 50%. When 10(3) focus-forming units of unpassaged CJN virus were dried in NDM and administered to subjects who licked the dried material, 100% (8 of 8) became infected. The effect of Lysol brand disinfectant spray (LDS) was next examined. Although NDM provided some protection against inactivation by LDS, spraying under conditions recommended by the manufacturer consistently caused the CJN virus titer to decrease greater than 5 log10. Consumption of CJN virus (10(3) focus-forming units) sprayed with LDS caused no infection in 14 subjects, whereas 13 of 14 subjects who consumed the unsprayed virus became infected (P less than 0.00001). The methods developed in this study could be used to test the effects of other disinfectants on the spread of infectious rotavirus from inanimate surfaces to humans.

Adolescent

[Myocardial infarct size and left ventricular function in diabetic patients].

We determined the relationship between myocardial infarct size (MIS) estimated by electrocardiographic measurements of infarct size (QRS score) and left ventricular function estimated by angiographically left ventricular ejection fraction (EF). MIS estimated by QRS score were the same in both DM and NDM (5.2 +/- 0.5 vs 4.3 +/- 0.4: p greater than 0.05), but EF in DM was significantly lower than in NDM (43.1 +/- 1.4 vs 51. +/- 1.1%: p less than 0.05). There was clear linear correlation between MIS and EF in NDM (r = -0.71) but not in DM. EF was much lower in DM than in NDM even at the same QRS score level. There were no differences in blood pressure, serum lipid levels, age, and the site of the myocardial infarction. The most likely explanation for this appears to be due to a previous left ventricular disease in DM.

Aged

[Purging of leukemic cells from mouse marrow and tumor suspensions with lysosomotropic agent N-dodecyl morpholine].

The lysosomotropic agent N-dodecyl morpholine (NDM) showed a marked killing of mice leukemic cells in vitro: 100% killing of L7811 leukemic cells (10(6) cells/ml) at a concentration of 15 micrograms/ml. Bone marrow of 615 mice containing 5% L7811 leukemic cells was treated with NDM and then infused into normal 615 mice. Mean survival times (MST) were 16.3 +/- 1.78 days and 15.8 +/- 2.32 days for control group and solvent group respectively, while the MST of groups treated with NDM were more than 40 days. When the marrow was infused into lethally irradiated mice, those mice receiving NDM-purged marrow died of radiation disease instead of leukemia. But when the number of marrow cells infused was increased to 2 x 10(6) cells/mouse, the mice survived for significantly longer times than did control group mice or those of the group infused with 10(6) cells/mouse.

Animals