Traditional Japanese herbal medicine Hochuekkito protects development of sepsis after nasal colonization in mice.

INTRODUCTION: Streptococcus pneumoniae, a commensal in the nasopharynx, can cause invasive pneumococcal diseases (IPDs). To prevent the aggravation of IPDs, it is important to enhance host immune defense against S. pneumoniae. Hochuekkito (HET) is expected to have an immunostimulatory effect against infections. METHODS: HET was administrated by gavage to adult BALB/cA mice before and after intranasal inoculation of S. pneumoniae. We evaluated the effect of HET on pneumococcal nasal colonization and subsequent development of lethal pneumococcal infections. RESULTS: No effect on nasal colonization was observed, but HET significantly reduced bacterial count in the blood, decreased the incidence of bacteremia, and improved survival. HET also reduced nasal tissue damage 3 days after intranasal infection. Neutrophils from HET-treated mice showed significantly higher bactericidal activity against S. pneumoniae in the presence of the serum from the HET group compared with from the control group. CONCLUSIONS: The non-specific immunostimulatory effect of HET is suggested by this study to be effective in preventing the progression in IPDs and provided insights into novel strategy in the post-pneumococcal vaccine era.

Contrast-Enhanced MRI Is Useful for Prognostic Prediction on Idiopathic Bilateral Simultaneous Facial Nerve Palsy: A Case Report and Literature Review.

Idiopathic bilateral facial nerve palsy is a rare condition and presents a diagnostic and prognostic challenge. Specifically, when bilateral nerves are damaged, it is difficult to predict the prognosis. We showcase the usefulness of contrast-enhanced magnetic resonance imaging (MRI) by providing information about localization and severity of degeneration of facial nerve. A 70-year-old Japanese man presented with bilateral simultaneous facial nerve palsy of House-Brackmann Grade VI on both sides. Contrast-enhanced MRI revealed bilateral intensity enhancement of intratemporal facial nerves. The signal intensity was higher on the left side than on the right side. Facial nerve decompression was performed on the left side. The left facial nerve palsy was finally improved eight months after the onset, while the right side was improved just under two months after the onset. Contrast-enhanced MRI for facial nerve palsy can provide valuable information for the evaluation of damaged facial nerves. In our patient's case, it was useful as a prognostic predictor of bilateral facial nerve palsy.

Factors affecting the antimicrobial changes during treatment for acute otitis media in Japan: A retrospective cohort study using classification and regression trees (CART) analysis.

OBJECTIVES: Factors that affect the change of first-line antimicrobial agents were investigated to further promote their appropriate use. METHODS: This descriptive study used an electronic medical records database. Total 16,353 of the 199,896 patients enrolled between 1996 and 2019 met the inclusion criteria and formed the overall pediatric acute otitis media (AOM) cohort. The factors leading to the change in first-line antimicrobial agents within 14 days were analyzed using classification and regression trees (CART) analysis. RESULTS: This antimicrobial treatment cohort, involved 4860 cases of AOM alone and 9567 cases of AOM with other diseases. The size of the medical facility based on number of beds and historical duration of patient registration impacted on antimicrobial changes. CONCLUSIONS: The current results show that hospital-wide or nation-wide antimicrobial stewardship promotion could be the most influencing factor for antimicrobial changes. Particularly in cases of AOM where other diseases coexist, a more accurate diagnosis and definition of treatment failure of first-line drug are suggested to be important while establishing future treatment strategies. The current study is important to promote appropriate antimicrobial use for AOM treatment.

Nucleic acid sensing Toll-like receptors 3 and 9 play complementary roles in the development of bacteremia after nasal colonization associated with influenza co-infection.

Streptococcus pneumoniae can cause mortality in infant, elderly, and immunocompromised individuals owing to invasion of bacteria to the lungs, the brain, and the blood. In building strategies against invasive infections, it is important to achieve greater understanding of how the pneumococci are able to survive in the host. Toll-like receptors (TLRs), critically important components in the innate immune system, have roles in various stages of the development of infectious diseases. Endosomal TLRs recognize nucleic acids of the pathogen, but the impact on the pneumococcal diseases of immune responses from signaling them remains unclear. To investigate their role in nasal colonization and invasive disease with/without influenza co-infection, we established a mouse model of invasive pneumococcal diseases directly developing from nasal colonization. TLR9 KO mice had bacteremia more frequently than wildtype in the pneumococcal mono-infection model, while the occurrence of bacteremia was higher among TLR3 KO mice after infection with influenza in advance of pneumococcal inoculation. All TLR KO strains showed poorer survival than wildtype after the mice had bacteremia. The specific and protective role of TLR3 and TLR9 was shown in developing bacteremia with/without influenza co-infection respectively, and all nucleic sensing TLRs would contribute equally to protecting sepsis after bacteremia.

Case Report: Solid variant of papillary thyroid carcinoma in a young adult with Turner syndrome with chronic thyroiditis.

Turner syndrome is associated with an increased risk of developing several neoplasms. In particular, a clinical feature of Turner syndrome with chronic thyroiditis implies a relationship with thyroid malignancies. We report a very rare case of a solid variant of papillary thyroid carcinoma that was identified during a follow-up of chronic thyroiditis in a 22-year-old woman with Turner syndrome. The patient had no notable history of radiation exposure. No genetic mutations relating to the occurrence of the solid variant of papillary thyroid carcinoma, including RET/PTC rearrangements and mutations in the BRAF or RAS, were detected by a gene panel test, namely, the Oncomine™ Dx Target test. To the best of our knowledge, this is the first report of a solid variant of papillary thyroid carcinoma in a young adult with Turner syndrome with chronic thyroiditis. Our case suggests that in patients with Turner syndrome, there may be different pathogeneses from those previously reported, including exposure to radiation or known genetic mutations for the development of a solid variant of papillary thyroid carcinoma.

Prime-boost-type PspA3 + 2 mucosal vaccine protects cynomolgus macaques from intratracheal challenge with pneumococci.

BACKGROUND: Although vaccination is recommended for protection against invasive pneumococcal disease, the frequency of pneumococcal pneumonia is still high worldwide. In fact, no vaccines are effective for all pneumococcal serotypes. Fusion pneumococcal surface protein A (PspA) has been shown to induce a broad range of cross-reactivity with clinical isolates and afford cross-protection against pneumococcal challenge in mice. Furthermore, we developed prime-boost-type mucosal vaccines that induce both antigen-specific IgG in serum and antigen-specific IgA in targeted mucosal organs in previous studies. We investigated whether our prime-boost-type immunization with a fusion PspA was effective against pneumococcal infection in mice and cynomolgus macaques. METHODS: C57BL/6 mice were intramuscularly injected with fusion PspA combined with CpG oligodeoxynucleotides and/or curdlan. Six weeks later, PspA was administered intranasally. Blood and bronchoalveolar lavage fluid were collected and antigen-specific IgG and IgA titers were measured. Some mice were given intranasal Streptococcus pneumoniae and the severity of infection was analyzed. Macaques were intramuscularly injected with fusion PspA combined with CpG oligodeoxynucleotides and/or curdlan at week 0 and week 4. Then, 13 or 41 weeks later, PspA was administered intratracheally. Blood and bronchoalveolar lavage fluid were collected and antigen-specific IgG and IgA titers were measured. Some macaques were intranasally administered S. pneumoniae and analyzed for the severity of pneumonia. RESULTS: Serum samples from mice and macaques injected with antigens in combination with CpG oligodeoxynucleotides and/or curdlan contained antigen-specific IgG. Bronchial samples contained antigen-specific IgA after the fusion PspA boosting. This immunization regimen effectively prevented S. pneumoniae infection. CONCLUSIONS: Prime-boost-type immunization with a fusion PspA prevented S. pneumoniae infection in mice and macaques.

Case report: Cochlear implantation was effective for progressive bilateral severe hearing loss associated with Kawasaki disease.

Sensorineural hearing loss associated with Kawasaki disease has been increasingly reported, but its etiology remains unclear. Most reported cases of sensorineural hearing loss associated with Kawasaki disease have been mild and reversible during acute or subacute phases. However, bilateral severe hearing loss as a complication of Kawasaki disease can cause delays in cognitive and speech development. A 4-year-old Japanese boy treated for Kawasaki disease had right-side moderate and left-side profound sensorineural hearing loss on the 141st day after onset of Kawasaki disease. Despite systemic steroid pulse treatment, hearing loss remained in both sides. After the recurrence of Kawasaki disease, hearing on the right side progressively worsened, meaning there was now severe hearing loss on both sides. Left cochlear implantation performed on the 1065th day after the onset of Kawasaki disease improved the patient's hearing and his ability to communicate. Sensorineural hearing loss associated with Kawasaki disease may progress over a long period and cause bilateral severe hearing loss, although past reports showed occurrence during acute or subacute phases. The clinical course of our patient suggests that intense inflammation caused by Kawasaki disease could be related to prolonged hearing loss. Cochlear implantation seems to be effective for sensorineural hearing loss associated with Kawasaki disease.

Chondroma Arising from the Temporomandibular Joint: A Case Report.

Periarticular chondromas are common in the humerus and femur but rarely occur in the temporomandibular joint. We report a case of a chondroma in the anterior part of the ear. One year prior to his visit, a 53-year-old man became aware of swelling in the right cheek region which gradually increased in size. In the anterior part of the right ear, there was a palpable 25 mm tumor, elastic and hard, with poor mobility and without tenderness. A contrast-enhanced computed tomography CT showed a mass lesion with diffuse calcification or ossification in the upper pole of the parotid gland and areas of poor contrast within. A magnetic resonance imaging showed a low-signal mass lesion at the parotid gland with some high signals in both T1 and T2. Fine-needle aspiration cytology did not lead to diagnosis. Using a nerve monitoring system, the tumor was resected with normal tissue of the upper pole of the parotid gland in the same way as for a benign parotid tumor. Distinguishing between pleomorphic adenoma, including diffuse microcalcification of the parotid gland and cartilaginous tumors of the temporomandibular joint, may be sometimes difficult. In such cases, surgical resection may be a beneficial treatment option.

Maternal immunization with pneumococcal surface protein A provides the immune memories of offspring against pneumococcal infection.

Introduction: Streptococcus pneumoniae (S. pneumoniae) is one of the most widespread pathogens in the world and one of the largest infectious causes of infant mortality. Although current vaccines have various benefits, antibiotic resistance and the inability to vaccinate infants less than one year old demands the development of new protective strategies. One strategy, 'maternal immunization', is to protect infants by passive immunity from an immunized mother, although its mechanism is still not fully understood. Materials and methods: The current study aimed to acquire immunity against S. pneumoniae in infants by maternal immunization with pneumococcal common antigen, pneumococcal surface protein A (PspA). Four-week-old female mice were immunized with recombinant PspA intranasally twice a week for three weeks. Females were mated with age-matched males after immunization, and delivered offspring. Results: The week-old offspring derived from and fostered by immunized mothers had more anti-PspA-specific antibody producing cells in the spleen than those derived from sham-immunized mothers. The offspring were raised up to four weeks old and were subcutaneously stimulated with recombinant PspA. The levels of anti-PspA IgG in sera after stimulation were significantly higher in the offspring derived from the immunized mothers and the induced specific antibody to PspA showed protective efficacy against systemic pneumococcal infection. Discussion: Maternal immunization is suggested to be able to provide a sustained immune memory to offspring. The current study would be a milestone in the field of maternal immunization toward a universal pneumococcal vaccine.

The Roles of Transient Receptor Potential Vanilloid 1 and 4 in Olfactory Regeneration.

Olfactory disorders, which are closely related to cognitive deterioration, can be caused by several factors, including infections, such as COVID-19; aging; and environmental chemicals. Injured olfactory receptor neurons (ORNs) regenerate after birth, but it is unclear which receptors and sensors are involved in ORN regeneration. Recently, there has been great focus on the involvement of transient receptor potential vanilloid (TRPV) channels, which are nociceptors expressed on sensory nerves during the healing of damaged tissues. The localization of TRPV in the olfactory nervous system has been reported in the past, but its function there are unclear. Here, we investigated how TRPV1 and TRPV4 channels are involved in ORN regeneration. TRPV1 knockout (KO), TRPV4 KO, and wild-type (WT) mice were used to model methimazole-induced olfactory dysfunction. The regeneration of ORNs was evaluated using olfactory behavior, histologic examination, and measurement of growth factors. Both TRPV1 and TRPV4 were found to be expressed in the olfactory epithelium (OE). TRPV1, in particular, existed near ORN axons. TRPV4 was marginally expressed in the basal layer of the OE. The proliferation of ORN progenitor cells was reduced in TRPV1 KO mice, which delayed ORN regeneration and the improvement of olfactory behavior. Postinjury OE thickness improved faster in TRPV4 KO mice than WT mice but without acceleration of ORN maturation. The nerve growth factor and transforming growth factor ß levels in TRPV1 KO mice were similar to those in WT mice, and the transforming growth factor ß level was higher than TRPV4 KO mice. TRPV1 was involved in stimulating the proliferation of progenitor cells. TRPV4 modulated their proliferation and maturation. ORN regeneration was regulated by the interaction between TRPV1 and TRPV4. However, in this study, TRPV4 involvement was limited compared with TRPV1. To our knowledge, this is the first study to demonstrate the involvement of TRPV1 and TRPV4 in OE regeneration.

Improvement of Surgical View and Working Space at the Lower Pole by Three-Dimensional Exoscope-Assisted Coblation Tonsillectomy: A Case Series.

Advantages of hot devices for tonsillectomy, represented by coblation, have been highlighted in recent years. During hot technique tonsillectomy it is important to identify and coagulate the vessels of the tonsillar capsule, especially at the lower pole of the tonsil. Hot technique tonsillectomy under microscope or endoscope has therefore been recommended to achieve accurate identification of the microstructure of the surgical field. We have applied ORBEYE, a three-dimensional surgical exoscope system, to coblation tonsillectomy. Advantages of using ORBEYE include high definition and high magnification images, and flexibility of camera position and angle. This means there is an improved surgical view and working space, particularly at the lower pole during performance of coblation tonsillectomy. Here, we demonstrate that ORBEYE can be an effective surgical instrument in coblation tonsillectomy.

Bactericidal effect of lascufloxacin on HEp-2 cell-internalized group A Streptococcus.

INTRODUCTION: Although amoxicillin (AMPC) is recommended as first-line therapy for acute pharyngotonsillitis caused by group A streptococci (GAS), it often fails to eradicate infections. Internalization and subsequent intracellular survival of GAS are considered major mechanisms for penicillin therapeutic failure. It is, therefore, desirable to administer drugs that exert bactericidal effects on extracellular and intracellular GAS. In this study, we aim to investigate the bactericidal effects of lascufloxacin (LSFX) on internalized GAS in HEp-2 cells. MATERIALS AND METHODS: The GAS strain M1 and clinical isolate strain #2 were used in this study. Following treatment of GAS-infected human pharyngeal carcinoma epithelial HEp-2 cells with LSFX or AMPC, internalized GAS cells were recovered. The concentrations of LSFX and AMPC were equivalent to 1 × and 2 × MIC for strain M1. Culture medium was used as a control. Time-lapse and fluorescence images of GAS invading HEp-2 cell were obtained. LIVE/DEAD fluorescence staining was used to confirm the viability of internalized GAS. RESULTS: LSFX significantly reduced the number of cell-internalized M1 and #2 GAS strains compared to the control (p < 0.01) in a dose-dependent manner. However, AMPC did not reduce this in both strains. Both live and dead intracellular GAS were confirmed in HEp-2 cells exposed to LSFX. In contrast, intracellular GAS survived in HEp-2 cells exposed to AMPC and in the control. CONCLUSION: LSFX elicits significant bactericidal effects on cell-internalized GAS, hence it may represent a potent therapeutic option for patients with acute pharyngotonsillitis in whom AMPC treatment has failed.

A rare case of Pseudomonas aeruginosa enteritis induced by pembrolizumab.

A 72-year-old male had pseudomonal enteritis related to pembrolizumab. Chemotherapy for hypopharyngeal carcinoma with lung metastasis comprised cisplatin, 5-FU, and pembrolizumab. On day 14 of chemotherapy treatment he had a sudden prominent abdominal bulge, decreased consciousness, and drop in blood pressure in septic shock. CT scan showed marked intestinal gas through to intrahepatic bile ducts. Pseudomonas aeruginosa was simultaneously detected in both blood and stool cultures. Intestinal endoscopy revealed ulcerative lesions from the transverse colon to the rectum. Pathological investigations indicated apoptosis of the villus. The patient was diagnosed with pseudomonal enteritis induced by immune-related adverse events from the use of pembrolizumab. Treatment by corticosteroid and meropenem were subsequently switched to cefepime and metronidazole, and this successfully improved his colitis. In this new era of biological-targeted drugs and as clinical experience grows, we recommend a high level of alertness for potential diagnosis of infectious complications.

Respiratory quinolones can eradicate amoxicillin-induced mature biofilms and nontypeable Haemophilus influenzae in biofilms.

OBJECTIVES: Biofilm is thought to be involved in the persistent bacterial infections caused by nontypeable Haemophilus influenzae (NTHi). This study aims to evaluate the efficacy of antibiotics against NTHi biofilms. METHODS: A 96-wells pin replicator assay was applied for evaluation of antimicrobial efficacies against NTHi biofilms. The NTHi IH-202 strain for the standard and 10 clinical strains were evaluated, as well as the viability of NTHi in biofilms after antimicrobial exposures. RESULTS: Biofilms formed by IH-202 strain accumulated during incubation. AMPC if not high concentrations, neither reduce or inhibit biofilm formation, nor eradicate matured NTHi biofilms. The NTHi in matured biofilm were alive after exposure to amoxicillin (AMPC). Even high concentration of AMPC produced live NTHi after suspension of exposure, while tosufloxacin and garenoxacin inhibited biofilm formation of NTHi and eradicated matured biofilms. The respiratory quinolones, but not AMPC, killed NTHi in biofilms even at sub-MIC. CONCLUSIONS: NTHi persists in biofilms, even after exposure to AMPC. These findings may eventually lead to a better understanding of effective use of antibiotics to eradicate NTHi growing as biofilms, or even to the development of novel therapeutic agents for treating patients with mucosal NTHi biofilm infections. Meanwhile, respiratory quinolones are attractive agents in reducing NTHi biofilm formation and destroying established biofilm.

Investigation on the virulence of non-encapsulated Streptococcus pneumoniae using liquid agar pneumonia model.

INTRODUCTION: Since the introduction of pneumococcal conjugate vaccine, there have been warnings of an increase in infections caused by non-vaccine type of Streptococcus pneumoniae strains. Among them, nonencapsulated Streptococcus pneumoniae (NESp) has been reported to cause invasive infections, especially in children and the elderly. Due to low virulence, however, basic experimental reports on invasive infections are limited. METHODS: We applied a liquid-agar method to establish a mouse model of invasive NESp infection. Mice were intratracheally administered a bacterial suspension including agar. With this technique, we investigated the pathogenicity of NESp and the effect of Pneumococcal surface protein K (PspK), a specific surface protein antigen of NESp. NESp wild-type strain (MNZ11) and NESp pspK-deleted mutant strain (MNZ1131) were used in this study. The survival rate, number of bacteria, cytokine/chemokine levels in the bronchoalveolar lavage fluid, and histology of the lung tissue were evaluated. RESULTS: Mice that were intratracheally administered MNZ11 developed lethal pneumonia with bacteremia within 48 h. Conversely, MNZ1131 showed predominantly low lethality without significant pro-inflammatory cytokine production. NESp was found to cause severe pneumonia and bacteremia upon reaching the lower respiratory tract, and PspK was a critical factor of NESp for developing invasive infections. CONCLUSIONS: The current study demonstrated the ability of NESp to develop invasive diseases, especially in connection with PspK by use of a mouse pneumonia model.

Lateral approach contributes to shortened surgical time in video-assisted neck surgery (VANS) for thyroid nodule.

Background: Despite endoscopic thyroid surgery contributing to excellent cosmetic outcomes, it requires longer surgical time than open surgery. This study evaluates the factors associated with operative time in video-assisted neck surgery. Methods: We retrospectively reviewed patients who underwent hemithyroidectomy by video-assisted neck surgery at a single hospital between 2017 and 2021. The clinical parameters were evaluated: age, sex, body weight, body mass index, coexistence of Hashimoto thyroiditis, side of operation, surgical approach to thyroid (midline approach or lateral approach), operation time, amount of blood loss during surgery, maximum tumor diameter and tumor volume, and postoperative complications. These parameters were compared to investigate the association of operative time and surgical approach. Results: Seventy consecutive patients were enrolled in this study, the median age at operation was 50 years, and there were 6 (8.6%) men and 64 (91.4%) women. The median body weight and body mass index at operation were 56.6 kg and 21.5, respectively. Coexistence of Hashimoto thyroiditis was found in 17 (24.3%) patients. Significant differences were found between the groups with longer and shorter operation time than median 201 minutes in surgical approaches to the thyroid (P < .001) and the amount of bleeding during surgery (P = .039). There were no differences in other candidates between the groups. Median operation times were 242 minutes in midline approach and 131 minutes in lateral approach (P < .001). Conclusion: The lateral approach of video-assisted neck surgery to the thyroid can contribute to shortened surgical time in the case of benign thyroid nodules.

A case of concurrent occurrence of carcinoma showing thymus-like differentiation and follicular variant of papillary thyroid cancer in the same thyroid.

Carcinoma showing thymus-like differentiation (CASTLE) is a rare thyroid cancer. This is the first report of a case of concurrent occurrence of CASTLE with papillary thyroid carcinoma (PTC). A 66-year-old male patient had hoarseness with right vocal cord paralysis. Ultrasonography revealed a hypoechoic nodule in the inferior pole of the right thyroid lobe. Ultrasound-guided fine-needle aspiration cytology suggested differentiated thyroid cancer. The patient underwent total thyroidectomy with neck dissection. Pathological examination revealed two different thyroid cancers: a CASTLE and a follicular variant of PTC. Postoperative radiation therapy was performed. The patient was still alive after 5 year following the initial treatment without evidence of recurrence. The oncological management of patients with concurrent occurrence of different thyroid cancers should consider the biological behavior of both tumors.

A Novel Pneumococcal Surface Protein K of Nonencapsulated Streptococcus pneumoniae Promotes Transmission among Littermates in an Infant Mouse Model with Influenza A Virus Coinfection.

We established an infant mouse model for colonization and transmission by nonencapsulated Streptococcus pneumoniae (NESp) strains to gain important information about its virulence among children. Invasive pneumococcal diseases have decreased dramatically since the worldwide introduction of pneumococcal capsular polysaccharide vaccines. Increasing prevalence of nonvaccine serotypes, including NESp, has been highlighted as a challenge in treatment strategy, but the virulence of NESp is not well understood. Protective strategies against NESp colonization and transmission between children require particularly urgent evaluation. NESp lacks capsules, a major virulence factor of pneumococci, but can cause a variety of infections in children and older people. PspK, a specific surface protein of NESp, is a key factor in establishing nasal colonization. In our infant mouse model for colonization and transmission by NESp strains, NESp could establish stable nasal colonization at the same level as encapsulated serotype 6A in infant mice and could be transmitted between littermates. Transmission was promoted by NESp surface virulence factor PspK and influenza virus coinfection. However, PspK deletion mutants lost the ability to colonize and transmit to new hosts. Promotion of NESp transmission by influenza was due to increased susceptibility of the new hosts. PspK was a key factor not only in establishment of nasal colonization but also in transmission to new hosts. PspK may be targeted as a new candidate vaccine for NESp infection in children.

Impact of the practical guideline on appropriate usage of antimicrobial treatments for surgical site infections in reconstructive surgery of head and neck cancer.

OBJECTIVES: In 2016, Japanese Society of Chemotherapy and Japan Society for Surgical Infection presented the practical guideline for appropriate usage of antimicrobial agents to prevent postoperative infections. This study aims to exhibit the validity of the guideline as a series of effective strategies for prevention of surgical site infections (SSIs) during reconstructive surgery of the head and neck cancer. METHODS: We retrospectively evaluated patients who underwent head and neck reconstructive surgery with free or pedicle flaps in a single institute in Japan between July 2010 and July 2020. We evaluated the incidence of SSIs, patient backgrounds, and microbiological characteristics on the basis of antimicrobial prophylaxis recommended by the guideline. RESULTS: Enrolled in this study were 102 patients in our institution who underwent head and neck reconstructive surgery with free or pedicle flaps between July 2010 and July 2020. In the period between January 2018 to July 2020 after the SSI guideline was advocated (SSI guideline period), the ratio of administration of sulbactam/ampicillin (SBT/ABPC) was significantly higher (P < 0.001) and the duration of prophylactic antimicrobial treatment was significantly shorter than in the period between July 2010 to December 2017 before the SSI guideline was advocated (Pre-SSI guideline period) (P < 0.001). Incidence of SSIs were similar, even when antibiotic use was changed to be short-term single-agent administration in accordance with the practical guideline. CONCLUSIONS: Adherence to the current Japanese practical guideline on appropriate antimicrobial prophylaxis for SSIs can shorten the duration of usage of antimicrobial treatment without increasing the risk for occurrence of SSIs.

Neutrophil infiltration in co-housed littermates plays a key role in nasal transmission of Streptococcus pneumoniae in an infant mouse model.

Transmission plays an important role in establishing pneumococcal colonization. It comprises three key events: shedding to transmit, entering into a susceptible new host, and adhering to the mucosal surface. Shedding of pneumococci from the respiratory tract of a colonized host is a pivotal step in transmission. Using a co-housed littermate mouse model, we evaluated the importance of the susceptibility to colonization of Streptococcus pneumoniae TIGR4 strain shed from index pups to non-colonized naïve contact pups. Despite sufficient pneumococcal shedding from the colonized host, S. pneumoniae was not contagious between littermates. Neutrophils infiltrated the nasal mucosa of contact pups and contributed to susceptibility of pneumococcal colonization during the course of transmission. Rejection of pneumococcal colonization in the contact pups was associated with accumulation of neutrophils in the nasal mucosa. Inflammation, characterized by neutrophil infiltration, prevents newly entering pneumococci from adhering to the respiratory epithelium in contact mice, suggesting that it plays an important role in reducing the rate of transmission in the initial response of naïve susceptible hosts to pneumococcal acquisition. The initial response of contact mice may regulate neutrophil and/or macrophage infiltration and control the acquisition of existing pneumococci.