Updates
By Carol A. Kemper, MD, FACP, Clinical Associate Professor of Medicine, Stanford University, Division of Infectious Diseases; Santa Clara Valley Medical Center, Section Editor, Updates; Section Editor, HIV, is Associate Editor for Infectious Disease Alert.
PANDAS: Rare or Simply Non-existent?
Source: Shulman ST. Pediatric autoimmune neuropsychiatric disorders associated with streptococci (PANDAS): Update. Current Op Peds. 2009;21:127-130.
A recent case of a 17-year-old presenting with acute psychiatric symptoms and possible meningoencephalitis prompted examination of this review article on Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infection (PANDAS). The patient presented with acute-onset fever, mental status changes, and mild CSF pleocytosis (18 cells/mL), with otherwise normal CSF parameters. Evaluation, including radiographic studies and EEG, failed to identify an infectious etiology or other cause. While his mental status continued to wax and wane, he promptly defervesced, and a repeat CSF analysis four days later was unremarkable. Only an ASO titer was elevated at 748. The patient had no arthritis or carditis and no evidence of OCD or tic disorder, although his behavior was often bizarre, with facial grimaces.
Dr. Shulman nicely summarizes the current literature regarding the relationship between a group of neuropsychiatric disorders occurring in children ages 3 to puberty, including Sydenham's chorea, OCD and tic disorder (or Tourette's syndrome), and antecedent group A streptococcal (GAS) infection. The association between Sydenham's chorea and GAS is strongly supported by the literature, mostly because it occurs in patients with arthritis and/or carditis consistent with acute rheumatic fever. Recognition of this type of chorea may be complicated by symptom onset up to six months following GAS infection, when the ASO titer is often negative.
However, a cohort study found no association between OCD/tic disorder and GAS infection in 85% of cases. And no good evidence exists to support differences brain autoimmunity between patients with OCD/tic disorders and those without. Additional studies suggest that PANDAS, most of which do not fit the classical description of OCD/tic disorder, are over-diagnosed by community physicians.
Dr. Shulman concludes that the association between these neuropsychiatric disorders and GAS seems increasingly unlikely. Therefore, long-term antibacterial prophylaxis is not warranted, and there is no clinical evidence to support the use of plasma exchange or IVIG in these children.
In the end, it was revealed that our patient had a history of bipolar disorder, as well as recent ecstasy use, which provided a likelier explanation for his fever and bizarre behavior.
Isolation Precautions for Respiratory MRSA
Source: Gehanno JF, et al. Aerial dispersal of meticillin-resistant Staphylococcus aureus in hospital rooms by infected or colonised patients. J Hosp Infect. 2009;71:256-262.
Infection control policies vary regarding the use of face masks in patients with MRSA nasal or respiratory colonization or infection. To assess the potential for airspace contamination in such patients, duplicate air samples were collected within 0.5, 1, and 2-3 meters from the head of patients with MRSA respiratory tract infection (n = 20) or respiratory colonization (n = 4). Sixteen of the patients had received no antibiotics specific for MRSA before the sampling period. Control samples collected were obtained from three rooms before patients were admitted to the space.
Airspace samples were positive for 87.5% of the case patients; in contrast, airspace samples from the control rooms were all negative. Nearly half (49%) of 138 air samples were positive for MRSA, with a range of 1-78 cfu/culture plate (mean, ~7 cfu/plate). The distance from the head of the patient was not significant.
PFGE was used to examine 12 selected pairs of clinical and environmental isolates, demonstrating good concordance. Two major susceptibility profiles were observed among the clinical and environmental isolates, similar to strains circulating in the hospital during the study period. Environmental strains isolated from 13 of 21 rooms had a similar susceptibility profile, and the environmental and clinical isolates appeared to match. Isolates from the other eight rooms differed, with up to three different strains per room, and the clinical and environmental isolates did not appear to match.
These data suggest that MRSA is present in the airspace of most patients with respiratory MRSA infection or colonization, at least within 2-3 meters of the head of the patient. Whether this necessitates droplet or airborne precautions is debatable, but at the least use of regular paper masks seem warranted, especially in patients with cough or those requiring aerosolizing procedures, such as suctioning and respiratory therapy.
MRSA in HIV
Source: Shet A, et al. Colonization and subsequent skin and soft tissue infection due to methicillin-resistant Staphylococcus aureus in a cohort of otherwise healthy adults infected with HIV Type 1. J Infect Dis. 2009;200:88-93.
MRSA colonization appears to be more common in persons with HIV infection, although there is controversy whether this is due to behavioral and environmental factors or host immunity. Nasal and axillary colonization with MRSA was prospectively assessed in a group of 107 HIV-infected patients in New York City, and compared with 52 epidemiologically matched non-HIV-infected control subjects.
Over a period of one year, MRSA colonization was observed more frequently in persons with HIV than in those without (16.8% vs. 5.8%, p = .04). Twenty-one MRSA isolates were recovered from 18 individuals with HIV infection, 19 of which appeared to be clonally related, as determined by the presence of the spa Type 1 gene. Fifteen of these isolates were characterized as MRSA300 based on the presence of PVL, SCCmec type IVa, spa type 1, and ACME (arginine catabolic mobile element) genes. In contrast, the MSSA strains recovered were heterogeneous.
Susceptibility studies showed that nearly half of the MRSA isolates found in persons with HIV infection had either constitutive or inducible resistance to clindamycin. And, 38% showed high level resistance to mupirocin.
Ten (47.8%) of the HIV+ patients with MRSA colonization subsequently developed MRSA skin and soft tissue infection. Interestingly, this was a group of fairly health HIV+ patients (mean CD4 count, 612 cell/mm3, range 253-1401). The only significant risk factor identified for MRSA colonization in persons with HIV was a history of antibiotic use within the previous six months. The presence of a chronic skin condition, use of recreational drugs, and shared towels were not significant risk factors.
The Red Soils of Jordan: Fact or Wives Tale?
Source: Falkinham JO III, et al. Proliferation of antibiotic-producing bacteria and concomitant antibiotic production as the basis for the antibiotic activity of Jordan's red soils. Applied Environ Microbiol. 2009,75:2735-2741.
Scientists continue to search for new sources of antimicrobials. Some soils have an abiotic effect, meaning they adversely affect microbes because of their mineral content or composition. Other natural products may have a biotic, or microbial, basis for their healing properties. Intrigued by historical accounts and anecdotal reports of the beneficial healing properties of red soils found in the northwestern corner of Jordan, near the Mediterranean, Falkinham et al decided to investigate.
Jordan's red soils have been used, and continue to be used, in some parts, for treating skin infections and diaper rash. Typically, a clean area of soil is selected (without foot traffic), the superficial layer swept away, and the deeper soil collected, dried, and turned into powder or paste. This is, then, directly applied to the affected skin area.
Red soil specimens from two geographically distinct areas were collected for study. Experiments demonstrated progressive killing of both Staphylococcus aureus and Micrococcus luteus 12 and 22 days after inoculation into prepared soil specimens. No killing occurred when these same bacteria were inoculated into non-red agricultural soil specimens. Since autoclaved red soil had no killing effect on S. aureus or M. luteus strains inoculated into samples, Falkinham et al focused on a biotic effect.
Following inoculation of either S. aureus or M. luteus into soil samples, an increase in colony growth-creating zones of inhibition around S. aureus and M. luteus was observed (ranging from a 3.5- to 13-fold zone of inhibition). No increase in bacterial growth was observed in uninoculated soil samples. Similar results were observed against C. albicans. This bacterial growth was due to a complex of organisms, mostly consisting of Actinomycetes, various Lysobacter strains (many of which were slimy colonies with different pigmentation), and a bacillus species.
Although no baseline antibacterial activity was observed for any of the soil samples, methanol extracts of soil inoculated with either S. aureus or M. luteus showed antibacterial activity following three weeks of incubation. In contrast, by three weeks, boiled cell-free filtrates of similarly inoculated soil specimens demonstrated no activity. This suggested a specific compound, and not an enzyme, was being produced in response to inoculation with staph bacteria. Using HPLC, two compounds were subsequently identified, belonging to the actinomycin structural class of drugs, which were named Actinomycin C2 and Actinomycin C3.
Falkinham et al propose that the use of Jordan's red soil plasters, when applied directly to infected skin, stimulate the growth of antibiotic-producing microbes present in the soil, in effect providing topical antibacterial activity against common skin organisms, such as staphylococcus.
A recent case of a 17-year-old presenting with acute psychiatric symptoms and possible meningoencephalitis prompted examination of this review article on Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infection (PANDAS).You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content