Quantifying the size-resolved dynamics of indoor bioaerosol transport and control

Understanding the bioaerosol dynamics of droplets and droplet nuclei emitted during respiratory activities is important for understanding how infectious diseases are transmitted and potentially controlled. To this end, we conducted experiments to quantify the size-resolved dynamics of indoor bioaerosol transport and control in an unoccupied apartment unit operating under four different HVAC particle filtration conditions. Two model organisms (Escherichia coli K12 and bacteriophage T4) were aerosolized under alternating low and high flow rates to roughly represent constant breathing and periodic coughing. Size-resolved aerosol sampling and settle plate swabbing were conducted in multiple locations. Samples were analyzed by DNA extraction and quantitative polymerase chain reaction (qPCR). DNA from both organisms was detected during all test conditions in all air samples up to 7 m away from the source, but decreased in magnitude with the distance from the source. A greater fraction of T4 DNA was recovered from the aerosol size fractions smaller than 1 μm than E. coli K12 at all air sampling locations. Higher efficiency HVAC filtration also reduced the amount of DNA recovered in air samples and on settle plates located 3-7 m from the source.

Severity of symptoms, physical functioning and satisfaction in patients with lumbar spinal stenosis: a validation study of the Iranian version of the Swiss Spinal Stenosis Score

AIM

A common cause of low back pain is lumbar spinal stenosis (LSS). The Swiss Spinal Stenosis Score (SSS) is a well-known questionnaire that measures the severity of symptoms, physical functioning and patient's satisfaction in lumbar spinal stenosis. This study aimed to translate and validate the SSS in Iran.

METHODS

A prospective clinical validation study was performed. Forward-backward procedure was applied to translate the original questionnaires into Persian. A sample of patients with lumbar spinal stenosis completed the questionnaire twice: at pre- and postoperative (6 months follow-up) assessments. To test reliability the internal consistency was assessed by the Cronbach's alpha coefficient. Validity was evaluated using the known groups comparison. In addition the Oswestry Disability Index was used to perform convergent validity.

RESULTS

In all 121 patients were entered into the study. The mean age of patients was 62.3 (SD=10.2) years. The Cronbach's alpha coefficient for the SSS was 0.88. Validity was performed by known groups analysis and showed satisfactory results. The instrument discriminated well between the subgroups of patients who differed in age, severity of lumbar spinal stenosis, and the Self-Paced Walking Test (SPWT). The change in the Oswestry Disability Index strongly correlated with the change in patients' scores on the SSS; lending support to its good convergent validity (r=0.82; P<0.001).

CONCLUSION

The Iranian version of Swiss Spinal Stenosis Score performed well and the findings suggest that it is a valid measure of symptoms, physical functioning and satisfaction among patients with lumbar spinal stenosis.

Hemodynamic factors affecting the suitability of the donated heart and kidney for transplantation

BACKGROUND

Due to the loss of autonomic nervous system, precise control of the hemodynamic status in dead brain potential donors presents a clinical dilemma. In these patients, due to head trauma and cerebral edema, fluids administration is restricted. Moreover, the decreased central venous pressure may put the viability of the organs at risk.

OBJECTIVE

To investigate hemodynamic factors affecting the suitability of the donated heart and kidney for transplantation.

METHODS

Data were retrospectively collected from the maintained databases of all dead-brain donors (DBDs) admitted to our organ procurement unit (OPU) ICU between 1999 and 2008. In this study, laboratory variables in addition to demographic data were collected. The time between donor entrance to the DBD ICU and organ procurement, vital signs, hourly urine output, amount of IV fluid administered, and the dosage of vasopressor and desmopressin were recorded. The end-point of the study was organ suitability for organ retrieval.

RESULTS

A total of 132 dead brain donors were studied. The mean±SD age of the donors was 26.3±12.2 years. The main cause of brain death was multiple trauma (53%). The organ retrieval rate was 82.6% for the kidney, 59.8% for the liver, and 53% for the heart. 83 (63%) and 106 (80.3%) donors had suitable hearts and kidneys, respectively. 66 cases did not receive desmopressin (50.4%) at all. The mean±SD dose of desmopressin the donors received was 7±1 µg. There was a significant association between the suitability of these two organs for transplantation and the dosage of the administered desmopressin and volume of IV solution the donors received.

CONCLUSION

Fluid therapy and administration of desmopressin can improve the number and quality of retrieved organs from dead brain donors.

Rotavirus and central nervous system symptoms: cause or contaminant? Case reports and review

Rotavirus is a common cause of severe gastroenteritis in children. In 2 patients with rotavirus gastroenteritis who developed encephalopathy, rotavirus RNA was detected in the cerebrospinal fluid (CSF) by reverse transcription-polymerase chain reaction; in 1 patient, rotavirus RNA was detected on 2 occasions 3 weeks apart. There are increasing reports of cases in which patients who have seizures after an episode of rotavirus diarrhea have evidence of rotavirus in their CSF. A search of 2 large hospital discharge databases suggested that seizures are noted as part of the discharge diagnosis in the records of, at most, <4% of patients with rotavirus diarrhea versus 7% of patients with bacterial diarrhea. Although evidence suggesting that rotavirus is a cause of central nervous system sequelae remains inconclusive, the 2 case reports presented in this study further illustrate a possible association. Further study is required to determine whether detection of rotavirus in CSF represents a true pathogen, CSF contamination that occurs at the time of lumbar puncture or in the laboratory, or carriage of rotavirus RNA in trafficking lymphocytes.

Bloodstream infections in neonatal intensive care unit patients: results of a multicenter study

For identification of risk factors for bloodstream infection (BSI) among neonatal intensive care unit patients, prospective 6-month studies in three neonatal intensive care units were conducted. BSI was diagnosed in 42 of 376 (11.2%) enrolled infants. Pathogens included coagulase-negative staphylococci, Candida sp., Group B streptococci and Gram-negative species. Patients with BSIs were more likely to die during their neonatal intensive care unit stay than were patients who did not acquire BSIs (6 of 42 vs. 11 of 334, P = 0.007). BSI rate was highest in infants with birth weight < 1500 g (relative risk (RR) = 6.8, P < 0.001), those treated with H-2 blockers (RR = 4.2, P < 0.001) or theophylline (RR = 2.8, P < 0.001) and those with admission diagnoses referable to the respiratory tract (RR = 3.7, P < 0.001). Infants who developed BSI were more severely ill on admission than other infants (median physiologic stability index 13 vs. 10 (P < 0.001) and were of lower gestational age (28 vs. 35 weeks, P < 0.001). In logistic regression analysis, risk of BSI was independently associated only with very low birth weight, respiratory admission diagnoses and receipt of H-2 blockers. Risk of isolation of a pathogen from blood culture was independently associated with Broviac, umbilical vein or peripheral venous catheterization > 10, 7 or 3 days, respectively, at one insertion site. Rate of isolation of a pathogen was higher (9 of 59 (15%)) within 48 hours of a measurable serum interleukin 6 concentration than an interleukin 6 level of 0 pg/ml (10 of 159 (6%), P = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Pediatric streptococcal toxic shock syndrome

Two children who presented with fever, rash, and hypotension were found to have group A beta hemolytic streptococcal toxic shock syndrome. These cases are reported to remind physicians who care for acutely ill children that exotoxin-producing streptococci can produce clinical features and multisystem failure similar to staphylococcal toxic shock syndrome.

Reliability of polymerase chain reaction in the detection of human immunodeficiency virus infection in children

During a 3-year period we followed 128 human immunodeficiency virus (HIV) antibody-positive children ages 6 days to 11 years clinically and with an HIV diagnostic panel consisting of antibody (by enzyme-linked immunosorbent assay and confirmed by indirect fluorescence assay or Western blot), p24 antigen detection, HIV isolation from peripheral blood culture and molecular detection of HIV nucleic acids by polymerase chain reaction (PCR). The PCR procedure included 30 cycles of amplification using two separate gag primer pairs (SK38/39 and SK101/145), followed by detection with probes to areas amplified (SK19 and SK102). Results of PCR were available within 48 hours and were sensitive (97%) and specific (100%). PCR should be obtained on all children exposed perinatally, and aggressive management should be undertaken for those found to be positive.

Immunogenicity and reactogenicity of Haemophilus influenzae type b-meningococcus group B outer membrane protein conjugate vaccine in children 2-60 months of age

Haemophilus influenzae b - Neisseria meningitidis group B outer membrane protein conjugate vaccine (Hib-OMP) was given to 571 children 2-60 months of age. Two doses of Hib-OMP were given, 2 months apart, to 2-11 month old infants, and a single dose to children 12-60 month old. Sera were obtained from a subset of vaccinees at each immunization, and at follow-up 1 month and 1 year after immunization. Geometric mean antibody concentration (micrograms/ml) before and after full immunization were respectively 0.111 and 3.549 for 2-3 month old, 0.108 and 5.048 for 4-5 month old, 0.082 and 6.933 for 6-11 month old; they were 0.103 and 3.500 for 12-17 month old, 0.167 and 7.791 for 18-23 month old and 0.243 and 12.781 for children greater than or equal to 24 months. Detectable antibody (greater than or equal to 0.125 micrograms/ml) failed to develop in 2/399 (0.5%) after primary immunization, and 12/252 (4.8%) lost detectable antibody 1 year later. Six of these 12 infants were less than 12 month old. The vaccine was immunogenic as early as 3-5 months of age. The need for booster immunization needs to be assessed.

Randomized comparative study of ampicillin/sulbactam vs. ceftriaxone for treatment of soft tissue and skeletal infections in children

In a prospective study 105 children hospitalized with soft tissue infection, 11 children with suppurative arthritis and 9 children with osteomyelitis were treated with either parenterally administered ampicillin/sulbactam or ceftriaxone. Treatment was randomized using a computer-generated table in a 2:1 fashion: 84 patients received ampicillin/sulbactam and 41 patients received ceftriaxone. Organisms isolated from wound site or blood cultures included Staphylococcus aureus (33), Streptococcus pyogenes (19), Haemophilus influenzae (9) including 4 beta-lactamase-positive organisms, Streptococcus pneumoniae (5), Neisseria gonorrhoeae (3) and 9 other organisms. Clinical and bacteriologic response was satisfactory in 100% of the ampicillin/sulbactam-treated patients and in 93% of the ceftriaxone-treated patients. Two patients with S. aureus infections treated with ceftriaxone had a delayed response and required change in therapy to parenterally administered oxacillin. Ampicillin/sulbactam represents a potentially useful single agent for the treatment of cellulitis and bone or joint infections in pediatric patients.