Community-onset methicillin-resistant Staphylococcus aureus associated with antibiotic use and the cytotoxin Panton-Valentine leukocidin during a furunculosis outbreak in rural Alaska

BACKGROUND: Community-onset methicillin-resistant Staphylococcus aureus (CO-MRSA) reports are increasing, and infections often involve soft tissue. During a CO-MRSA skin infection outbreak in Alaska, we assessed risk factors for disease and whether a virulence factor, Panton-Valentine leukocidin (PVL), could account for the high rates of MRSA skin infection in this region. METHODS: We conducted S. aureus surveillance in the outbreak region and a case-control study in 1 community, comparing 34 case patients with MRSA skin infection with 94 control subjects. An assessment of traditional saunas was performed. S. aureus isolates from regional surveillance were screened for PVL genes by use of polymerase chain reaction, and isolate relatedness was determined by use of pulsed-field gel electrophoresis (PFGE). RESULTS: Case patients received more antibiotic courses during the 12 months before the outbreak than did control subjects (median, 4 vs. 2 courses; P=.01) and were more likely to use MRSA-colonized saunas than were control subjects (44% vs. 13%; age-adjusted odds ratio, 4.6; 95% confidence interval, 1.7-12). The PVL genes were present in 110 (97%) of 113 MRSA isolates, compared with 0 of 81 methicillin-susceptible S. aureus isolates (P<.001). The majority of MRSA isolates were closely related by PFGE. CONCLUSION: Selective antibiotic pressure for drug-resistant strains carrying PVL may have led to the emergence and spread of CO-MRSA in rural Alaska.     

Anesthesia and the developing brain: a way forward for clinical research

It is now well established that many general anesthetics have a variety of effects on the developing brain in animal models. In contrast, human cohort studies show mixed evidence for any association between neurobehavioural outcome and anesthesia exposure in early childhood. In spite of large volumes of research, it remains very unclear if the animal studies have any clinical relevance; or indeed how, or if, clinical practice needs to be altered. Answering these questions is of great importance given the huge numbers of young children exposed to general anesthetics. A recent meeting in Genoa brought together researchers and clinicians to map a path forward for future clinical studies. This paper describes these discussions and conclusions. It was agreed that there is a need for large, detailed, prospective, observational studies, and for carefully designed trials. It may be impossible to design or conduct a single study to completely exclude the possibility that anesthetics can, under certain circumstances, produce long‐term neurobehavioural changes in humans; however , observational studies will improve our understanding of which children are at greatest risk, and may also suggest potential underlying etiologies, and clinical trials will provide the strongest evidence to test the effectiveness of different strategies or anesthetic regimens with respect to better neurobehavioral outcome.     

Parenchymal preserving anatomic resections result in less pulmonary function loss in patients with Stage I non-small cell lung cancer

Background

A suggested benefit of sublobar resection for stage I non-small cell lung cancer (NSCLC) compared to lobectomy is a relative preservation of pulmonary function. Very little objective data exist, however, supporting this supposition. We sought to evaluate the relative impact of both anatomic segmental and lobar resection on pulmonary function in patients with resected clinical stage I NSCLC.

Methods

The records of 159 disease-free patients who underwent anatomic segmentectomy (n?=?89) and lobectomy (n?=?70) for the treatment of stage I NSCLC with pre- and postoperative pulmonary function tests performed between 6 to 36 months after resection were retrospectively reviewed. Changes in forced expiratory volume in one second (FEV₁) and diffusion capacity of carbon monoxide (DLCO) were analyzed based upon the number of anatomic pulmonary segments removed: 1–2 segments (n?=?77) or 3–5 segments (n?=?82).

Results

Preoperative pulmonary function was worse in the lesser resection cohort (1–2 segments) compared to the greater resection group (3–5 segments) (FEV_{1(%predicted)}: 79% vs. 85%, p?=?0.038; DLCO_(%predicted): 63% vs. 73%, p?=?0.010). A greater decline in FEV₁ was noted in patients undergoing resection of 3–5 segments (FEV_{1 (observed)}: 0.1 L vs. 0.3 L, p?=?0.003; and FEV_{1 (% predicted)}: 4.3% vs. 8.2%, p?=?0.055). Changes in DLCO followed this same trend (DLCO_(observed): 1.3 vs. 2.4 mL/min/mmHg, p?=?0.015; and DLCO_{(% predicted)}: 3.6% vs. 5.9%, p?=?0.280).

Conclusions

Parenchymal-sparing resections resulted in better preservation of pulmonary function at a median of one year, suggesting a long-term functional benefit with small anatomic segmental resections (1–2 segments). Prospective studies to evaluate measurable functional changes, as well as quality of life, between segmentectomy and lobectomy with a larger patient cohort appear justified.

     

Extensive non-small cell lung cancer treated with mitomycin, cisplatin, and vindesine (MiPE): a Southwest Oncology Group Study

Ninety-seven previously untreated patients with metastatic non-small cell lung cancer were treated with combination chemotherapy consisting of mitomycin (10 mg/m2) on Day 1, cisplatin (50 mg/m2) on Days 1 and 22, and vindesine (3 mg/m2) on Days 1 and 22 (MiPE). MiPE was repeated at 6-week intervals until disease progression or unacceptable toxicity. The overall response rate was 33%. There were seven complete responses (7%) and 25 partial responses (26%). The median progression-free interval for responding patients was 7 months. Median survival for all patients was 5 months, with 16% surviving 1 year. One patient died from sepsis while neutropenic. The results with MiPE treatment for patients with non-small cell lung cancer compare favorably to other mitomycin-vinca combinations previously tested in the Southwest Oncology Group.     

Multivalent Pneumococcal Protein Vaccines Comprising Pneumolysoid with Epitopes/Fragments of CbpA and/or PspA Elicit Strong and Broad Protection

Immunization with the pneumococcal proteins pneumolysin (Ply), choline binding protein A (CbpA), or pneumococcal surface protein A (PspA) elicits protective responses against invasive pneumococcal disease in animal models. In this study, we used different mouse models to test the efficacy of a variety of multivalent protein-based vaccines that comprised various combinations of full-length or peptide regions of the immunogens Ply, CbpA, or PspA: Ply toxoid with the L460D substitution (referred to herein as L460D); L460D fused with protective peptide epitopes from CbpA (YPT-L460D-NEEK [YLN]); L460D fused with the CD2 peptide containing the proline-rich region (PRR) of PspA (CD2-L460D); a combination of L460D and H70 (L460D+H70), a slightly larger PspA-derived peptide containing the PRR and the SM1 region; H70+YLN; and other combinations. Each mouse was immunized either intraperitoneally (i.p.) or subcutaneously (s.c.) with three doses (at 2-week intervals) of the various antigen combinations in alum adjuvant and then challenged in mouse models featuring different infection routes with multiple Streptococcus pneumoniae strains. In the i.p. infection sepsis model, H70+YLN consistently provided significant protection against three different challenge strains (serotypes 1, 2, and 6A); the CD2+YLN and H70+L460D combinations also elicited significant protection. Protection against intravenous (i.v.) sepsis (type 3 and 6A challenge strains) was largely dependent on PspA-derived antigen components, and the most protection was elicited by H70 with or without L460D or YLN. In a type 4 intratracheal (i.t.) challenge model that results in progression to meningitis, antigen combinations that contained YLN elicited the strongest protection. Thus, the trivalent antigen combination of H70+YLN elicited the strongest and broadest protection in diverse pneumococcal challenge models.     

Focused antibody response to influenza linked to antigenic drift

The selective pressure that drives antigenic changes in influenza viruses is thought to originate from the human immune response. Here, we have characterized the B cell repertoire from a previously vaccinated donor whose serum had reduced neutralizing activity against the recently evolved clade 6B H1N1pdm09 viruses. While the response was markedly polyclonal, 88% of clones failed to recognize clade 6B viruses; however, the ability to neutralize A/USSR/90/1977 influenza, to which the donor would have been exposed in childhood, was retained. In vitro selection of virus variants with representative monoclonal antibodies revealed that a single amino acid replacement at residue K163 in the Sa antigenic site, which is characteristic of the clade 6B viruses, was responsible for resistance to neutralization by multiple monoclonal antibodies and the donor serum. The K163 residue lies in a part of a conserved surface that is common to the hemagglutinins of the 1977 and 2009 H1N1 viruses. Vaccination with the 2009 hemagglutinin induced an antibody response tightly focused on this common surface that is capable of selecting current antigenic drift variants in H1N1pdm09 influenza viruses. Moreover, amino acid replacement at K163 was not highlighted by standard ferret antisera. Human monoclonal antibodies may be a useful adjunct to ferret antisera for detecting antigenic drift in influenza viruses.