Methicillin-resistant coagulase-negative staphylococci in the community: high homology of SCCmec IVa between Staphylococcus epidermidis and major clones of methicillin-resistant Staphylococcus aureus

BACKGROUND

Data on community spread of methicillin-resistant coagulase-negative staphylococci (MR-CoNS) are scarce. We assessed their potential role as a reservoir of staphylococcal cassette chromosome mec (SCCmec) IVa, the leading SCCmec subtype in community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA).

METHODS

Nasal carriage of MR-CoNS was prospectively investigated in 291 adults at hospital admission. MR-CoNS were characterized by SCCmec typing, long-range polymerase chain reaction (PCR) for SCCmec IV, and multiple-locus variable-number tandem repeat analysis (MLVA) for Staphylococcus epidermidis (MRSE) strains. Three SCCmec IVa elements were fully sequenced.

RESULTS

The carriage rate of MR-CoNS was 19.2% (25.9% and 16.5% in patients with and patients without previous exposure to the health care system, respectively; P = .09). MR-CoNS strains (n = 83, including 58 MRSE strains with highly heterogeneous MLVA patterns) carried SCCmec type IVa (n = 9, all MRSE), other SCCmec IV subtypes (n = 9, including 7 MRSE), other SCCmec types (n = 15), and nontypeable SCCmec (n = 50). Long-range PCR indicated structural homology between SCCmec IV in MRSE and that in MRSA. Complete sequences of SCCmec IVa from 3 MRSE strains were highly homologous to those available for CA-MRSA, including major clones USA300 and USA400.

CONCLUSIONS

MR-CoNS are probably disseminated in the community, notably in subjects without previous exposure to the health care system. MRSE, the most prevalent species, may act as a reservoir of SCCmec IVa for CA-MRSA.

Survival trends in critically ill HIV-infected patients in the highly active antiretroviral therapy era

Introduction

The widespread use of highly active antiretroviral therapy (ART) has reduced HIV-related life-threatening infectious complications. Our objective was to assess whether highly active ART was associated with improved survival in critically ill HIV-infected patients.

Methods

A retrospective study from 1996 to 2005 was performed in a medical intensive care unit (ICU) in a university hospital specialized in the management of immunocompromised patients. A total of 284 critically ill HIV-infected patients were included. Differences were sought across four time periods. Risk factors for death were identified by multivariable logistic regression.

Results

Among the 233 (82%) patients with known HIV infection before ICU admission, 64% were on highly active ART. Annual admissions increased over time, with no differences in reasons for admission: proportions of patients with newly diagnosed HIV, previous opportunistic infection, CD4 counts, viral load, or acute disease severity. ICU and 90-day mortality rates decreased steadily: 25% and 37.5% in 1996 to 1997, 17.1% and 17.1% in 1998 to 2000, 13.2% and 13.2% in 2001 to 2003, and 8.6% in 2004 to 2005. Five factors were independently associated with increased ICU mortality: delayed ICU admission (odds ratio (OR), 3.04; 95% confidence interval (CI), 1.29 to 7.17), acute renal failure (OR, 4.21; 95% CI, 1.63 to 10.92), hepatic cirrhosis (OR, 3.78; 95% CI, 1.21 to 11.84), ICU admission for coma (OR, 2.73; 95% CI, 1.16 to 6.46), and severe sepsis (OR, 3.67; 95% CI, 1.53 to 8.80). Admission to the ICU in the most recent period was independently associated with increased survival: admission from 2001 to 2003 (OR, 0.28; 95% CI, 0.08 to 0.99), and between 2004 and 2005 (OR, 0.13; 95% CI, 0.03 to 0.53).

Conclusions

ICU survival increased significantly in the highly active ART era, although disease severity remained unchanged. Co-morbidities and organ dysfunctions, but not HIV-related variables, were associated with death. Earlier ICU admission from the hospital ward might improve survival.

Genesis of a KPC-producing Klebsiella pneumoniae after in vivo transfer from an imported Greek strain

We document here the in vivo transfer of bla(KPC-2) between intensive care unit-acquired and a commensal strain of K. pneumoniae in a French patient after his repatriation from Greece. This first report of an emerging KPC-producing strain in France raises further concerns about the spread of carbapenem resistance among Enterobacteriaceae.

Etiologies and outcome of acute respiratory failure in HIV-infected patients

Objective

To assess the etiologies and outcome of acute respiratory failure (ARF) in HIV-infected patients over the first decade of combination antiretroviral therapy (ART) use.

Methods

Retrospective study of all HIV-infected patients (n = 147) admitted to a single intensive care unit (ICU) for ARF between 1996 and 2006.

Results

ARF revealed the diagnosis of HIV infection in 43 (29.2%) patients. Causes of ARF were bacterial pneumonia (n = 74), Pneumocystis jirovecii pneumonia (PCP, n = 52), other opportunistic infections (n = 19), and noninfectious pulmonary disease (n = 33); the distribution of causes did not change over the 10-year study period. Two or more causes were identified in 33 patients. The 43 patients on ART more frequently had bacterial pneumonia and less frequently had opportunistic infections (P = 0.02). Noninvasive ventilation was needed in 49 patients and endotracheal intubation in 42. Hospital mortality was 19.7%. Factors independently associated with mortality were mechanical ventilation [odds ratio (OR) = 8.48, P < 0.0001], vasopressor use (OR, 4.48; P = 0.03), time from hospital admission to ICU admission (OR, 1.05 per day; P = 0.01), and number of causes (OR, 3.19; P = 0.02). HIV-related variables (CD4 count, viral load, and ART) were not associated with mortality.

Conclusion

Bacterial pneumonia and PCP remain the leading causes of ARF in HIV-infected patients in the ART era. Hospital survival has improved, and depends on the extent of organ dysfunction rather than on HIV-related characteristics.

Effect of trunk inclination on lower limb joint and lumbar moments in able men during the stance phase of gait

BACKGROUND

Though the effect of imposed trunk posture affects walking patterns little is known about the effect of natural orientation of the trunk on gait. The objectives of this study are to test if the lower limb joint and thoraco-lumbar moments are similar in subjects who maintain an average natural forward or backward trunk inclination during gait and verify if the lower limbs are equally affected.

METHODS

Twenty-five young men were divided according to their natural backward or forward trunk inclination during level walking. Ankle, knee, hip and thoraco-lumbar moments were calculated by an inverse dynamic approach for the two limbs. A two-way ANOVA was performed on peak lower limb moments. A one-way ANOVA was performed on thoraco-lumbar peak moments.

FINDINGS

There was a main effect for both trunk inclinations and lower limb sides but no interaction. For the forward leaners, the duration of hip extension moment was longer (P<0.001) while the hip flexion moment was 1.3 times smaller (P<0.001). Differences between the lower limb sides were noted in all joints but at push-off of the stance phase only. The two thoraco-lumbar extension moments were, respectively, 1.4 times higher for the forward leaners while the two flexion moments were approximately 1.4 times higher for the backward leaners.

INTERPRETATIONS

The backward leaners propel themselves with a strong hip flexor activity at push-off while the forward leaners use their hip muscles throughout stance. These results support the idea that trunk inclinations and moment variations are associated with the type of walking patterns.

New separation method for organic and inorganic selenium compounds based on anion exchange chromatography followed by inductively coupled plasma mass spectrometry

We describe a new method for separating the organic and inorganic selenocompounds methaneseleninic acid, selenite, selenate, methylselenocysteine, selenocystine as well as both selenomethionine and its oxidized form. The separation is performed on a Hamilton PRP-X100 column. According to the literature, the oxidized form of selenomethionine-which is easily formed-is eluted close to the dead volume when this column is used. The choice of parahydroxybenzoic acid as mobile phase enabled us to elute all of these species after this oxidized form, resulting in better identification and quantification. The factors determining separation (eluent concentration, pH, gradient) were optimized via an experimental design. Application of the method to yeast and commercial tablets showed that the principal Se compound present was selenomethionine, which was also present in its oxidized form.

[Coasting and ovarian stimulation protocols in high-responder patients undergoing assisted conception]

Over-responsive patients are at risk of ovarian hyperstimulation, which may lead to severe complications. The choice of ovarian stimulation protocol or the use of a coasting (gonadotrophins suspension) with its associated risk of too strong ovarian response will be discussed herein. As for in vitro fertilization stimulation protocols, the best are probably those which use steadily increasing low doses of gonadotrophins, associated to GnRH agonists (low-dose protocols) or those which complete a double hypophyseal inhibition (estro-progestative association and GnRH agonists). GnRH antagonists may also reduce the risk of ovarian hyperstimulation, by estradiol drop. Outside the context of in vitro fertilization GnRH continuous administration or low -dose gonadotrophin stimulation are the best options. A coasting will be performed when an excess follicle response is documented. Under strict hormonal follow-up and within four days it allows achieving a high rate of pregnancy with a lower risk of hyperstimulation. Compared to other therapies of hyperstimulation syndrome, the coasting allows to avoid cycle cancellation or freezing of all embryos.

Effect of Body Morphology on Standing Balance in Adolescent Idiopathic Scoliosis

OBJECTIVES

The objective of this study was to determine the effect of body somatotype on standing balance in girls with adolescent idiopathic scoliosis (AIS) who are under observation but not wearing a body brace.

DESIGN

In all, 74 girls participated in this study to form the able-bodied (n = 36) and the AIS (n = 38) groups, having an average age of 13 yrs. Quiet standing balance was tested using a force platform. Afterward, subjects in each group were divided according to their dominant body somatotype, namely endomorphs (fatness), mesomorphs (muscular), or endomorphic ectomorphs (lean).

RESULTS

The center of pressure measured in the anteroposterior position was closer to the heels for the AIS ectomorphic group by approximately 14 mm (P = 0.00497). Only the AIS mesomorphic group displayed a statistically significant 12-mm shift to the right in their center of pressure (P = 0.01211) compared with the able-bodied girls of the same morphotype. In the endomorphic group, the sway area was statistically higher for the scoliotic subjects (P = 0.00839). The distances traveled by the AIS subjects were all statistically longer for all three body morphologic somatotypes.

CONCLUSION

Different postural responses seem to be dependent on body somatotypes. The endomorphic AIS girls had a larger sway area than their able-bodied counterparts while maintaining a similar center of pressure position. The AIS ectomorphic girls had a tendency to lean further back than a comparable able-bodied group. This could be emphasizing a hypokyphotic trunk attitude and increasing the risk of spinal deformity progression. The AIS mesomorphic subjects characterized by a large muscular and bony structure had a tendency to position their center of mass more to their right, indicating less postural adaptability and a stiffer trunk.

Main functional roles of knee flexors/extensors in able-bodied gait using principal component analysis (I)

This study was undertaken to demonstrate how principal component analysis (PCA) can be used to detect the main functional structure of actions taken by knee flexors/extensors during able-bodied gait. PCA was applied as a classification and curve structure detection method for knee sagittal muscle moment developed during walking of 20 young, healthy male subjects. Over 90% of the information provided by the first three principal components (PCs) was chosen for further biomechanical interpretation. PCA was able to identify the three main functional contributions of knee sagittal muscle moment during able-bodied gait, namely control balance, foot clearance/limb preparation and shock absorption.

Gait pattern classification of healthy elderly men based on biomechanical data

OBJECTIVES

To distinguish the gait patterns of young subjects from those of elderly men using three-dimensional (3D) gait data, to determine if elderly subjects displayed other than a typical gait pattern, and to identify which parameters best describe them.

DESIGN

Nonrandomized study in which video and force plate data were collected at the subject's own free walking speed and used in a 3D inverse dynamic model. Cluster analysis was chosen to identify the gait families, and analyses of variance were performed to determine which parameters were different.

SETTING

A gait laboratory.

PARTICIPANTS

The sample of convenience involved a single but mixed group consisting of 16 able-bodied elderly subjects (mean age, 62yrs) and 16 able-bodied young subjects aged between 20 and 35 years.

MAIN OUTCOME MEASURES

Phasic and temporal gait parameters, as well as the 3D muscle powers developed in the joints of the right lower limb during the gait cycle.

RESULTS

The walking patterns in elderly subjects were found to be different from those of the young adults. Three elderly gait families or groups forming a specific gait pattern were identified, and differences were found in the phasic and temporal parameters as well as in 6 peak muscle powers. Four of the peak powers occurred in the sagittal plane, and half of them were related to the hip.

CONCLUSIONS

Biomechanical parameters can be used to classify the gait patterns of young and elderly men using cluster analysis rather than age alone. The muscle powers in elderly subjects are perturbed throughout the gait cycle and not only at push-off. It appears that the plane in which the peak powers occurred was related to their occurrence in the gait cycle. Variability in the gait patterns of elderly subjects could reflect natural adaptations or compensations. These should not be indicative of a deficient gait or be misconstrued as some age-related pathology.