In vitro activity of ceftazidime-avibactam against clinical isolates of Enterobacterales and Pseudomonas aeruginosa from sub-Saharan Africa: ATLAS Global Surveillance Program 2017-2021

OBJECTIVES

To report the in vitro susceptibility of Enterobacterales (n = 3905) and Pseudomonas aeruginosa (n = 1,109) isolates, collected from patients in sub-Saharan Africa (four countries) in 2017-2021, to a panel of 10 antimicrobial agents with a focus on ceftazidime-avibactam activity against resistant phenotypes and β-lactamase carriers.

METHODS

MICs were determined by CLSI broth microdilution and interpreted using both 2022 CLSI and EUCAST breakpoints. β-lactamase genes were identified in select β-lactam-nonsusceptible isolate subsets using multiplex PCR assays.

RESULTS

Among Enterobacterales, 96.2% of all isolates were ceftazidime-avibactam-susceptible (MIC90, 0.5 µg/mL), including all serine carbapenemase-positive (n = 127), 99.6% of ESBL-positive, carbapenemase-negative (n = 730), 91.9% of multidrug resistant (MDR; n = 1817), and 42.7% of DTR (difficult-to-treat resistance; n = 171) isolates. Metallo-β-lactamase (MBL) genes were identified in most (n = 136; 91.2%) ceftazidime-avibactam-resistant isolates (3.5% of all Enterobacterales isolates). Ceftazidime-avibactam percent susceptible values ranged from 99.5% (Klebsiella species other than Klebsiella pneumoniae) to 92.5% (K. pneumoniae) for the various Enterobacterial taxa examined. Greater than 90% of Enterobacterales isolates from each country (Cameroon, Ivory Coast, Nigeria, South Africa) were ceftazidime-avibactam-susceptible. Among P. aeruginosa, 88.9% of all isolates were ceftazidime-avibactam-susceptible (MIC90, 16 µg/mL). Most (88.5%) MBL-negative, meropenem-resistant (n = 78), 68.1% of MDR (n = 385), and 19.2% of DTR isolates (n = 99) were ceftazidime-avibactam-susceptible. MBL genes were identified in 43.1% of ceftazidime-avibactam-resistant isolates (n = 53; 4.8% of all P. aeruginosa isolates). Country-specific ceftazidime-avibactam percent susceptible values for P. aeruginosa ranged from 94.1% (Cameroon) to 76.2% (Nigeria).

CONCLUSION

Reference in vitro antimicrobial susceptibility testing demonstrated that most recent Enterobacterales (96%) and P. aeruginosa (89%) clinical isolates from four sub-Saharan African countries were ceftazidime-avibactam susceptible.

Development of nanofibrillar morphologies in poly(l-lactide)/poly(amide) blends: role of the matrix elasticity and identification of the critical shear rate for the nodular/fibrillar transition

Bio-based poly(l-lactide)/poly(amide-11) blends (PLA/PA11, 80/20 w/w) and poly(l-lactide)/poly(amide-6) blends (PLA/PA6, 80/20 w/w) are processed by twin-screw extrusion followed by injection-moulding and key rheological parameters controlling their morphologie are investigated. The same work is done using the same PLA modified by a multi-step reactive extrusion route with an epoxy-based chain extender to obtain modified poly(lactide)/poly(amide-11) (PLA-j/PA11 80/20 w/w) blends. The morphologies of the extruded materials and of the injection moulded parts are characterized by SEM and their formation is deeply discussed via rheological investigation to highlight the contribution of viscosity, elasticity and interfacial tension. The existence of a critical shear rate related to the transition from nodular to fibrillar morphology is highlighted and the results are in good agreement with the condition of fibrillation Ca/Ca_(crit) ≥ 4. Interestingly, with the exception of PLA/PA6 specimens, all blends obviously display uniform thin-thread fibrillar morphologies after injection-moulding. Compared with pure PLA, a drastic increase of the ductility was observed in the blends exhibiting a fiberlike structure without meanwhile sacrificing the stiffness. This study confirms that, through the appropriate choice of blend components (viscosity and elasticity ratio, flow conditions, interfacial tensions) the in situ fibrillation concept provides access, at a reasonable cost, to new materials with improved thermomechanical performances, without sacrificing weight and ability to be recycled.

A critical share rate exists, above which the droplet/fibril transition occurs during the injection moulding process. The elasticity ratio controls the morphology formation as well as the viscosity ratio and the interfacial tension.

A small proportion of community-associated methicillin-resistant Staphylococcus aureus bacteraemia, compared to healthcare-associated cases, in two South African provinces

We compared the proportion of cases of community-associated and healthcare-associated methicillin-resistant Staphylococcus aureus (CA-MRSA and HA-MRSA, respectively) bacteraemia among patients at five hospitals in the Gauteng and Western Cape provinces in South Africa and described the molecular characteristics and antimicrobial susceptibility trends. This was a cross-sectional study using data collected by enhanced surveillance for S. aureus bacteraemia. A total of 2511 cases of S. aureus bacteraemia were identified from January 2013 to January 2016. Among 1914 cases of S. aureus, 557 (29.1%) cases were identified as MRSA infection. Forty-four cases (44/1914 [2.3%] of all S. aureus cases) were considered CA-MRSA infection and 513/1914 (26.8% of all cases) had HA-MRSA infection; the majority were neonates. CA-MRSA constituted 7.9% (44/557) of all cases of MRSA infection. Staphylococcus aureus isolates demonstrated significantly reduced susceptibility to the following classes of antimicrobial agents: macrolides, tetracyclines, aminoglycosides and cotrimoxazole, in 2015 compared to 2013 (p < 0.05). Of the 557 MRSA isolates, 484 (87%) were typed for SCCmec elements and spa types: the most common SCCmec type was type III (n = 236, 48.76%), followed by type IV (n = 144, 29.76%). The most common spa types were t037 (n = 229, 47.31%) and t1257 (n = 90, 18.60%). Of 28 isolates selected for multilocus sequence typing (MLST), the most common sequence types (STs) were ST239 and ST612 of clonal complex 8 (CC8) (n = 8 each) and a novel ST (ST4121) was obtained for one isolate. This study demonstrates that S. aureus bacteraemia is common in South African academic centres and characterised by HA-MRSA SCCmec types III and IV. A small proportion of CA-MRSA cases were caused by a few different sequence types.

Acute kidney injury and mortality in hematopoietic stem cell transplantation: A single-center experience

Hematopoietic stem cell transplant (HSCT) is a life-saving procedure for patients with several malignant and nonmalignant hematological disorders. Acute kidney injury (AKI) is a common complication after HSCT. The aim of the study was to identify the incidence and outcomes of AKI associated with HSCT in our center. Sixty-six HSCT recipients from October 2008 to March 2014 at Christian Medical College, Ludhiana, were followed up till July 31, 2014. RIFLE criteria utilizing serum creatinine was used to diagnose and stage AKI. Mortality and AKI were the primary outcomes studied. The risk of AKI in relation to conditioning regimen, type of HSCT (allogeneic and autologous), co-morbidities, graft versus host disease, drug toxicity, and veno-occlusive disease were analyzed. Sixty-five patients were included in the study. Male: Female ratio was 3.6:1 with a median age of 17 years (1.5-62). Forty-nine (75.4%) patients had AKI over 3 months, R 17 (26.2%), I 19 (29.2%), and F 13 (20%). AKI occurred at a mean of 19.4 ± 29.2 days after the HSCT. AKI was more commonly observed in patients undergoing allogeneic versus autologous HSCT (85.2% in allogeneic vs. 27.8% in autologous, P = 0.005). Mortality was seen in 20 patients (30.8%) in 3 months. AKI in the first 2 weeks (P < 0.016) was a significant risk factor for mortality. Incidence of AKI in HSCT is high and accounts for significant mortality and morbidity. RIFLE classification of AKI has prognostic significance among HSCT patients with an incremental trend in mortality.

AIDS-related mycoses: the way forward

The contribution of fungal infections to the morbidity and mortality of HIV-infected individuals is largely unrecognized. A recent meeting highlighted several priorities that need to be urgently addressed, including improved epidemiological surveillance, increased availability of existing diagnostics and drugs, more training in the field of medical mycology, and better funding for research and provision of treatment, particularly in developing countries.

An assessment of the risk factors for type 2 diabetes among women in rural Jamaica

This project examined risk factors (lifestyle, socio-economic and cultural) for Type 2 diabetes among 890 women in rural Jamaica in comparison to national and international trends via the Behavioural Risk Factor Surveillance System (BRFSS) and further analysis via the Kruskal Wallis and Mann-Whitney U tests. Nonparametric tests explored the relationship of body mass index (BMI) and risk factors. Women above age 36 years, sedentary women and women with health insurance showed a significant increase in BMI. Seventh Day Adventists had significantly lower BMIs compared to Protestants. Prevalence of Type 2 diabetes in rural Jamaica is complicated by the lack of adequate health insurance, health practitioners (including dieticians and social workers), and vigorous public awareness campaigns, as well as high healthcare costs. Recommendations include the establishment of a comprehensive plan targeting women to reduce their risk factors for Type 2 diabetes, including early diagnoses, continuing education for healthcare providers and community mobilization among churches, schools, banks, pharmacies and other entities.

Right spatial neglect after left hemisphere stroke: qualitative and quantitative study

OBJECTIVES

Comparatively little research has been conducted on right neglect after left brain damage. The authors sought to assess contralateral neglect in subacute left hemisphere stroke patients using a comprehensive test battery validated in a large control group after right hemisphere stroke.

METHODS

Seventy-eight left hemisphere stroke patients were assessed. The test battery included a preliminary assessment of anosognosia and visual extinction, a clinical assessment of gaze orientation and personal neglect, and paper-and-pencil tests of spatial neglect in the peripersonal space. Only nonverbal tests were used.

RESULTS

Drawing and cancellation tasks revealed neglect in 10 to 13% of patients. The combined battery was more sensitive than any single test alone. A total of 43.5% of patients showed some degree of neglect on at least one measure. Anatomic analyses showed that neglect was more common and severe when the posterior association cortex was damaged.

CONCLUSIONS

The frequency of occurrence of right neglect was, as expected, much lower than that reported in a study using the same assessment battery in right brain damage stroke patients. Nevertheless, neglect was found in a substantial proportion of patients at a subacute stage, suggesting that it should be considered in the rehabilitation planning of left brain damage stroke patients.

Sensitivity of clinical and behavioural tests of spatial neglect after right hemisphere stroke

OBJECTIVES

The lack of agreement regarding assessment methods is responsible for the variability in the reported rate of occurrence of spatial neglect after stroke. The aim of this study was to assess the sensitivity of different tests of neglect after right hemisphere stroke.

METHODS

Two hundred and six subacute right hemisphere stroke patients were given a test battery including a preliminary assessment of anosognosia and of visual extinction, a clinical assessment of gaze orientation and of personal neglect, and paper and pencil tests of spatial neglect in the peripersonal space. Patients were compared with a previously reported control group. A subgroup of patients (n=69) received a behavioural assessment of neglect in daily life situations.

RESULTS

The most sensitive paper and pencil measure was the starting point in the cancellation task. The whole battery was more sensitive than any single test alone. About 85% of patients presented some degree of neglect on at least one measure. An important finding was that behavioural assessment of neglect in daily life was more sensitive than any other single measure of neglect. Behavioural neglect was considered as moderate to severe in 36% of cases. A factorial analysis revealed that paper and pencil tests were related to two underlying factors. Dissociations were found between extrapersonal neglect, personal neglect, anosognosia, and extinction. Anatomical analyses showed that neglect was more common and severe when the posterior association cortex was damaged.

CONCLUSIONS

The automatic rightward orientation bias is the most sensitive clinical measure of neglect. Behavioural assessment is more sensitive than any single paper and pencil test. The results also support the assumption that neglect is a heterogeneous disorder.

[Presenting a battery for assessing spatial neglect. Norms and effects of age, educational level, sex, hand and laterality]

The aim of this study was to build up a battery for assessing spatial neglect, then to analyse the norms and potential effects of age, education level, sex, hand used, and laterality. It was also to contribute evaluating the pseudoneglect phenomenon described by Heilman, which consists in a tendency of normal subjects to neglect the right peripersonal space. Tasks selected were presented to important groups of normal subjects, most often larger than 450. The battery comprised of a bell cancellation test, scene copy, clock drawing, two line bisection tasks, identification of overlapping figures, text reading, writing task, and the representational task of the France map. For each of them, different variables were selected, especially investigating the difference between performance in the right and the left hemispaces. This study allowed defining the threshold values (percentiles 5 and 95) for deciding of the pathological character of a patient performance. It also showed that the pseudoneglect phenomenon is more obvious in some tasks such as line bisection, and probably also in the representational task of the France map and writing. His importance and at times his side were influenced by the factors we studied, with between tasks differences, but also by the nature of the task to be performed, and especially his verbal component.

Impaired cardiac functional reserve and left ventricular hypertrophy in adult sheep after prenatal dexamethasone exposure

We have shown that exposure of pregnant ewes to dexamethasone (11.5 mg/d for 2 days) at 27 days of gestation (term, 150 days) led to increased blood pressure and cardiac output in adult offspring. In this study, we hypothesized that dexamethasone-induced hypertension is associated with left ventricular hypertrophy and a reduced cardiac functional reserve (CO(max-0)). Six control animals (group C) and five dexamethasone-exposed animals (group D) were volume-loaded with Hemaccel until the wedge pressure was 13 mm Hg (baseline). The wedge pressure was held constant during an infusion of dobutamine at incremental doses (0.4 to 12 microgram/kg/min) while blood pressure and cardiac output were measured. The same protocol was repeated in each animal 5 days later under mild general anesthesia (1.5% isoflurane), when transthoracic echocardiography (M-mode) was obtained. Group D showed a reduced CO(max-0) in response to dobutamine during both conscious (89+/-22 versus 150+/-25 mL/kg/min in control; P<0.01) and anesthetized states (91+/-38 versus 156+/-56 mL/kg/min in control; P<0.05). Reduced CO(max-0) in group D was associated with higher left ventricular mass index compared with group C (2.6+/-0.67 versus 1.8+/-0.51 g/kg; P<0.05). In addition, group D showed a reduced cardiac contractility reserve (FS(max-0)) in response to dobutamine (21+/-22% versus 54+/-34% in group C; P<0.05). An impaired cardiac functional reserve in group D was associated with increased left ventricular type I collagen content. In conclusion, brief prenatal exposure to dexamethasone led to the development of hypertension, left ventricular hypertrophy, and reduced cardiac functional reserve in adult life.

Justification of statistical overlap theory in programmed temperature gas chromatography: thermodynamic origin of random distribution of retention times

A specific distribution of compounds' standard-state changes of enthalpy and entropy between mobile and stationary phases in programmed temperature gas chromatography (PTGC) is shown to produce the Poisson distribution of retention times often postulated in statistical-overlap theory (SOT). A three-part model is proposed, in which the enthalpy change is Poisson distributed, the average entropy change depends on the enthalpy change, and the actual entropy change varies in a uniformly random manner about the average entropy change. To test the model, the entropy and enthalpy changes of 350 aliphatic and aromatic hydrocarbons in petroleum were calculated with commercial GC software. These changes are shown to follow the three-part model. The model then was used with Monte Carlo methods to mimic the enthalpy and entropy changes. The substitution of the mimicked enthalpy and entropy changes into an equation for the retention temperature in PTGC is shown to produce a Poisson distribution of retention times that is statistically significant. This finding establishes a scientific link between the thermodynamics governing retention in PTGC and the superficially ad hoc assumption of the Poisson retention time distribution in SOT. Similar thermodynamic distributions are found for flavors and fragrances and for tetrachlorodibenzo-p-dioxins and furans, which follow SOT based on the Poisson distribution, but not for polychloronaphthalenes, which do not follow that SOT.

Production of recombinant human type I procollagen homotrimer in the mammary gland of transgenic mice

The large scale production of recombinant collagen for use in biomaterials requires an efficient expression system capable of processing a large (> 400 Kd) multisubunit protein requiring post-translational modifications. To investigate whether the mammary gland of transgenic animals fulfills these requirements, transgenic mice were generated containing the alpha S1-casein mammary gland-specific promoter operatively linked to 37 Kb of the human alpha 1(I) procollagen structural gene and 3' flanking region. The frequency of transgenic lines established was 12%. High levels of soluble triple helical homotrimeric [(alpha 1)3] type I procollagen were detected (up to 8 mg/ml) exclusively in the milk of six out of 9 lines of lactating transgenic mice. The transgene-derived human procollagen chains underwent efficient assembly into a triple helical structure. Although proline or lysine hydroxylation has never been described for any milk protein, procollagen was detected with these post-translational modifications. The procollagen was stable in milk; minimal degradation was observed. These results show that the mammary gland is capable of expressing a large procollagen gene construct, efficiently assembling the individual polypeptide chains into a stable triple helix, and secreting the intact molecule into the milk.

Dysprosody after severe closed head injury: an acoustic analysis

OBJECTIVES

Neurological speech disorders (dysarthria and dysprosody) are known to be frequent sequelae after severe closed head injury. These disorders may dramatically alter communicative intent and accentuate social isolation. The aim was to provide an instrumental evaluation for prosodic production in a group of patients with severe closed head injury and to determine the correlations between prosodic production and neurobehavioural status.

METHODS

Fifteen patients, at the subacute stage after severe closed head injury, were studied and compared with 11 controls, matched for age, sex, and duration of education. Each subject was required to read aloud a French sentence "Je m'en vais samedi matin" (I am leaving saturday morning) under six different prosodic intonations (neutral, affirmation, interrogation, happiness, sadness, anger). The recorded sentences were analysed using a sound signal analysis software (Signalyse) allowing the measurement of signal intensity and fundamental frequency. Statistical analyses were carried out using repeated measures analysis of variance (ANOVA).

RESULTS

Patients with closed head injury were significantly less able than controls to modulate speech output (pitch and intensity) according to prosodic context. This deficit was particularly pronounced for the intonation feature of anger, question, and statement. No consistent correlations could be found between prosodic production and cognitive or behavioural data.

CONCLUSIONS

Acoustic analysis of pitch and intensity may show impairments of prosodic production after severe closed head injury, which may be useful in rehabilitation planning. This impairment does not seem to reflect the eventual cognitive and behavioural deficits of the patients, but rather a specific disorder of modulation of speech output.

Late cognitive and behavioural improvement following treatment of disabling orthopaedic complications of a severe closed head injury

Interactions of physical, emotional, cognitive and behavioural impairments after severe closed head injury (CHI) remain poorly understood. A 47-year-old man was referred to our department 13 months after a severe CHI. He demonstrated severe left hemiplegia and disabling orthopaedic complications (left hip infectious arthritis, after surgical treatment for heterotopic ossification). His hip was blocked and extremely painful. He was totally dependent for daily-life activities (Functional Independence Measure (FIM) score = 18). Moreover he exhibited severe cognitive and behavioural troubles, which had been stable for many months beforehand, e.g. complete disorientation for time and place, major memory disorders, agitation, anxiety, depression, irritability, disinhibition, aggressiveness and lack of initiative. Pain disappeared within a few weeks after treatment. Progressively, functional improvement occurred (sitting position, transfers, walking between parallel bars). The FIM score increased to 63. Aggressiveness, irritability and agitation disappeared. Surprisingly, neuropsychological assessment demonstrated parallel improvement of cognitive functions, especially in regard to orientation, and to a lesser degree attention and memory. Such an observation should encourage use of active treatment of physical disabilities, even in patients presenting with an apparently poor cognitive prognosis at a late stage of severe CHI.

Affective disorder in the neurological patient

An index sample of neurological patients diagnosed as clinically depressed (83) was compared with a "major depression" sample (43) and a "neurological sample" (44) who were free from psychiatric disorder. There was no difference in global Hamilton Scores between the index and the major depression sample. The latter, however, more often exhibited family and personal history of psychiatric illness, early awakening, guilt, suicidal ideas, shorter index episodes of depression, and better response to treatment. The three samples were followed up for a period of up to 5 years. The index sample did worse on follow-up than did the depressed and the neurological samples. The disease profiles of both the index and neurological samples were similar, but there were more cases of epilepsy in the former. The index sample responded badly to conventional antidepressant treatment. It is concluded that the presence of chronic affective disorder in the neurological patient has an adverse effect on prognosis.

Psychiatric morbidity following total and partial thyroidectomy

Thirty subjects were screened for psychiatric morbidity approximately 7 years after they had undergone a thyroid operation. Thirteen were identified as "cases" by the General Health Questionnaire. Total and partial thyroidectomy subjects were compared. The total thyroidectomy patients identified as "cases" showed lower values of plasma calcium and higher values of inorganic phosphate than the partial thyroidectomy "cases", but the difference failed to reach statistical significance. No clinical or biochemical differences were found between cases and non-cases, irrespective of the type of operation.

Macronuclear chromatin organization in Paramecium primaurelia

Chromatin organization and transcriptional activity in the macronucleus of the ciliate Paramecium primaurelia have been studied by electron microscopic examination of spread chromatin preparations. Under spreading conditions which inhibit the activity of endogenous nucleases and proteases, various morphologically distinct types of chromatin are seen: (1) Largely condensed chromatin in the form of 30-40 nm supranucleosomal globules which aggregate to form knobbly 40-60 nm fibres and unravel into 12 nm nucleosomal filaments; (2) In rapidly growing cells, extended chromatin arranged groups of 4-8 adjacent nucleofilaments, each bearing numerous and very densely packed lateral fibrils. These fibrils are 20 nm thick, have a smooth outline and extend to lengths of up to 3 micron. Such transcripts are grouped in units along the chromatin axis and are apparently organized in register in adjacent filaments; (3) In starved cells, extended nucleofilaments bearing only occasional RNP fibrils. These various morphological characteristics are discussed in terms of macronuclear transcriptional activity and the polyploid nature of macronuclei.