This study characterized the adverse events following immunization (AEFI) with the novel influenza A (H1N1) 2009 vaccine in Korea. Data on immunization and AEFI were collected between October 27, 2009 and March 15, 2010 through the national immunization registry and passive surveillance systems. The frequency of AEFI and serious adverse events (SAEs) were calculated according to age, sex, priority group, and vaccine type. In 13,758,527 vaccine recipients aged 6 months or older, 2,530 AEFI were reported (18.4 per 100,000 immunizations). The AEFI reporting rate was highest among people aged 10–19 years (29.6 per 100,000 immunizations) and was higher in female recipients than in male recipients (20.0 versus 16.7 per 100,000 immunizations). Most AEFIs were nonspecific systematic reactions that occurred within 24 h (77.4%) after vaccine administration. A total of 178 vaccine-related SAEs were identified, and vaccine-related mortalities were not reported. This study showed that the AEFI reporting rate after influenza A (H1N1) 2009 vaccinations was relatively high, especially in the younger population. Mild systemic reactions accounted for the majority of reported AEFI, and fatal SAEs were rare. This study also implied that passive surveillance might be an efficient safety monitoring system that can detect relatively rare AEFI.

Public health authorities recommend that isolation precautions for influenza should be continued for 7 days after illness onset or until 24 h after the resolution of symptoms, whichever event lasts longer. However, little data are available regarding the duration of isolation for patients with 2009 pandemic H1N1 (pH1N1). We recruited patients with confirmed pH1N1 virus infection at a 2,000-bed tertiary care center. Influenza viral loads from oropharyngeal swab specimens were serially determined by reverse transcriptase quantitative polymerase chain reaction every other day, and the risk factors for prolonged viral shedding were investigated. To evaluate the current recommendations for isolation precautions, we measured the intervals between symptom onset and the last viral RNA detection, and that between the last viral RNA detection and the point at which the patient was symptom-free for 24 h. From November 2009 to January 2010, 26 patients were enrolled, and viral RNA was detected in more than half of the eligible patients (10 of 19, 52.6%) for ≥7 days after symptom onset. While evaluating the policy for lifting quarantine, we found that viral RNA was detected in 4 of 15 patients (26.7%) beyond the recommended duration of isolation. In conclusion, viral RNA was detected in a substantial proportion of hospitalized patients even when they fulfilled the recommended conditions for lifting quarantine, and we believe that more prudence is required in this aspect.

We developed an enrichment medium for use with the loop-mediated isothermal amplification (LAMP) assay (enrichment media + LAMP assay) to quickly increase a very small number of Vibrio parahaemolyticus cells to the detection limit of the assay. Thirty-nine different enrichment media were prepared based on evaluating 12 potential ingredients. From our assessment of the 39 media, enrichment medium #36, which contained 2% sodium chloride, 1% proteose peptone no. 2, 0.1% trehalose, 0.5% α-ketoglutaric acid, 0.25% pyruvic acid, and 0.5% yeast extract (pH 8.6), was found to be most effective at enhancing the proliferation of V. parahaemolyticus during incubation for 3 h at 40°C. We compared the detection limits of the LAMP assay, the enrichment medium #36 + LAMP assay, and the cultivation method using bacterial cell and spiked shrimp sample tests. The detection limits of the LAMP assay, the medium #36 + LAMP assay, and the cultivation method were 10³, 10⁰–10^-1, and 10^-1 CFU ml^-1, respectively. Enrichment medium #36 promoted a 10³- to 10⁴-fold increase in the bacterial population, and the detection limit of the enrichment media + LAMP assay was the same as that of the cultivation method.

This study was conducted to determine the prevalence of antimicrobial resistance in Shiga toxin-producing Escherichia coli (STEC) O157 (n = 241) and O26 (n = 11) isolated from beef cattle and to characterize their antimicrobial resistance profiles. Resistance to dihydrostreptomycin was detected most frequently (STEC O157, 9.5%; STEC O26, 54.5%), followed by resistance to oxytetracycline (7.9%; 45.5%) and ampicillin (5.4%; 36.4%). Resistance to one or more antimicrobial agents was detected in 13.3% (32/241) of the STEC O157 isolates and 54.5% (6/11) of the STEC O26 isolates. The antimicrobial resistance rate in the STEC O26 isolates was significantly higher than that in the STEC O157 isolates (P = 0.002, Fisher’s exact test). The antimicrobial resistance rate in the STEC O157 isolates possessing both stx₁ and stx₂ genes was 26.3% (15/57), while that in the isolates possessing stx_2c gene alone was 3.9% (3/77). These findings suggest that the antimicrobial resistance in STEC O157 is associated with serogroups and the Shiga toxin genotype.

The aim of this study was to investigate the prevalence of β-lactamase-negative ampicillin-resistant (BLNAR) Haemophilus influenzae isolated from patients of a teaching hospital in Thailand. Eighty-eight isolates of H. influenzae were collected between September 2005 and March 2008. All isolates were identified and characterized for biotypes and capsular types. The β-lactamase production of these isolates was examined, and their susceptibility to the following 12 antimicrobial agents was determined: ampicillin (AMP), amoxicillin-clavulanate (AMC), cefotaxime (CTX), cefuroxime (CXM), meropenem (MEM), clarithromycin (CLR), telithromycin (TEL), tetracycline (TET), ciprofloxacin (CIP), levofloxacin (LEV), trimethoprim-sulfamethoxazole (SXT), and chloramphenicol (CHL). Of the 88 H. influenzae isolates, 69 (78.4%), 13 (14.8%), 4 (4.5%), and 2 (2.3%) were from the respiratory tract, pus, the genital tract, and blood, respectively. Half of the isolates were biotype II (44 isolates, 50%). The other half comprised biotypes I (23 isolates, 26.1%), III (15 isolates, 17.1%), and IV (6 isolates, 6.8%). All isolates were capsular non-typeable, except for 2 isolates that were type f. Antimicrobial susceptibility showed that all isolates were susceptible to AMC, CTX, MEM, TEL, CIP, and LEV (100%), whereas 96.6%, 94.3%, 80.7%, 68.2%, 50.0%, and 44.3% were susceptible to CXM, CLR, CHL, TET, AMP, and SXT, respectively. The β-lactamase-production rate of H. influenzae isolates was 40.9%, and the prevalence of BLNAR was 18.2%.

Pseudomonas aeruginosa is known to produce surfactants that are involved in its swarming motility behavior, such as rhamnolipids and their precursors―3-(3-hydroxyalkanoyloxy)-alkanoic acids (HAAs). In P. aeruginosa PAO1, swarming motility is inhibited by some fatty acids, including branched-chain fatty acids and unsaturated fatty acids. In the present study, addition of 12-methyltetradecanoic acid (12-MTA, anteiso-C15:0) to an agar medium markedly repressed surfactant activity in the extracellular fraction of a P. aeruginosa culture in a drop collapse assay. Further, an extracellular fraction of a culture of rhlA mutant P. aeruginosa, which did not produce both rhamnolipids and HAAs, showed a complete loss of surfactant activity and markedly reduced swarming activity. In contrast, an extracellular fraction of a culture of rhlB mutant P. aeruginosa, which produced HAAs but not rhamnolipids, showed moderate swarming activity and weak extracellular surfactant activity that was lost on the addition of 12-MTA to the agar medium. Expression of the rhlAB operon from the plasmid pMR2 restored normal swarming motility on 12-MTA-containing agar medium. Taken together, these findings indicate that 12-MTA reduced extracellular surfactant activity, thus resulting in a swarming defect in P. aeruginosa PAO1.

After national case-based surveillance for pandemic influenza A (H1N1) ceased on July 23, 2009, a daily case-based surveillance system was implemented in Maebashi City, Japan. All medical facilities in the city reported all patients who had positive rapid antigen tests for influenza A. When the epidemic exploded in late October, case-based surveillance for influenza-like illness (ILI) was implemented from November 3, 2009 until the end of the epidemic. A total of 7,781 influenza cases were reported between July 25 and November 2, 2009, with a cumulative incidence rate of 22.5 per 1,000 population. Nearly 70% of the patients were under 15 years old. Between November 3, 2009 and the end of March 2010, a total of 16,394 ILI cases were reported, with a cumulative incidence rate of 47.4 per 1,000 population. Of the ILI cases reported, 63% were in patients younger than 15 years old. Only one death with laboratory confirmation of the H1N1 2009 virus was reported during the epidemic. The age-specific reproduction number among children under 15 years of age was almost 1.40, whereas between children and adults (15 years of age and above) it was considerably less than 1.0. The reproduction number derived from the next-generation matrix using data from September 30 to October 14 was estimated to be 1.48 (95% confidence interval, 1.41-1.56). Among individuals under 15 years of age, the infection rate calculated using the final size equation under the assumption of no mitigation measures was nearly twice the rate reported during the epidemic. These findings indicate that the majority of the transmission of influenza A (H1N1) 2009 in the city occurred among children.

Clostridium botulinum produces large complex toxins, which include botulinum neurotoxin (BoNT) and auxiliary non-toxic proteins. We prepared monoclonal antibodies (mAbs) from mice that were immunized several times with BoNT/A after basal immunization with toxoid. We then examined the reactivities of these mAbs to BoNT and toxoid and showed that some mAbs reacted to only BoNT. This result indicates that the antigenicity of BoNT/A partially disappeared with formalin treatment. Some mAbs that specifically recognized either BoNT/A1 or BoNT/A2 were considered useful as detection antibodies specific for the BoNT/A subtype. Results of a neutralizing test with mAbs against either BoNT/A1 or BoNT/A2 showed that neutralizing antibody recognition sites were present in the light chain, heavy chain (N-terminal half), and heavy chain (C-terminal half) domains. Investigation of the different binding capabilities of the mAbs to BoNT and the complex toxin by immunoprecipitation suggested that the light chain of BoNT is exposed at the molecular surface of the complex toxin since there was no difference in the binding of light chain-specific mAb to BoNT and the complex toxin. The heavy chain is related to BoNT binding to non-toxic components, because the reactivity of the heavy chain to some mAbs was influenced by non-toxic components.

The aim of the present study was to determine the rate of device-associated infection (DAI) and the change in profiles and antimicrobial resistance patterns of the causative microorganisms in a medical–surgical intensive care unit (ICU), as well as to evaluate the effect of a new nationwide hospital infection control program (NHICP), which has been implemented in Turkey. In this study, 5,772 patients that were hospitalized for a total of 43,658 days acquired 1,321 DAIs, with an overall rate of 30.2% per 1,000 ICU days. Between 2004 (before the NHICP) and 2010, the incidence densities of catheter-associated urinary tract infection (CAUTI) decreased from 10.2 to 5.7 per 1,000 device-days (P < 0.0001), and central venous catheter-associated bloodstream infection (CVC-BSI) decreased from 5.3 to 2.1 per 1,000 device-days (P < 0.0001). However, ventilator-associated pneumonia increased from 27.0 to 31.5 per 1,000 device-days. Multidrug-resistant species rates increased from 5.8% to 76.6% (P < 0.0001) for Acinetobacter spp. and from 6.8% to 53.1% (P < 0.0001) for Pseudomonas aeruginosa. The extended-spectrum β-lactamase-producing Enterobacteriaceae rate increased from 23.1% to 54.2% (P = 0.01); the vancomycin-resistance rate among Enterococcus spp. increased from 0% in 2004 to 12.5% in 2010 (P = 0.0003). In conclusion, while a significant decrease was achieved in the incidences of CAUTI and CVC-BSI, the NHICP was not completely effective in our ICU. The high incidence of DAI and the increasing prevalence of multidrug-resistant microorganisms indicate that further interventions are urgently needed.

We identified naturally induced antibodies from malaria patients in Thailand and clarified the effect of the antibodies on gametocyte development. Fifty-nine percent of the Plasmodium falciparum-infected blood samples (17 of 29) fed to female Anopheles mosquitoes showed no oocyst infection. Seventeen percent of the samples (5 of 29) distorted the morphology and hampered the maturity of the gametocytes. A possible mechanism for the gametocyte inhibitory activity was shown by the binding of the plasma antibodies to live, immature, intraerythrocytic gametocytes during the incubation period. One hundred fifty-seven proteins specific to different gametocyte stages were explored to find the targets of the antisera that bound to the live gametocytes. However, no additional gametocyte transmission-blocking vaccine candidate was detected. Therefore, the development of alternative transmission-blocking vaccines in high-transmission areas should focus on the identification of more gametocyte antigens-inducing inhibitory antibodies that reduce gametocytemia.

In Sri Lanka, leptospirosis is a notifiable disease. In addition to having a routine disease reporting system, Sri Lanka has implemented a hospital-based sentinel surveillance system since 2004. This report discusses the findings of a descriptive analysis of the sentinel surveillance data collected from 2005 to 2008. Of the 4,000 suspected leptospirosis cases, 46.9% and 26.8% were recorded from the Western and Sabaragamuwa provinces, respectively. Most of the individuals were male (83.5%), and approximately 45.6% were aged 30–49 years. Farmers accounted for 16.5%, and laborers for 16.1%; however, the occupation of nearly half (44.8%) of the study population was unknown. More than half (53.9%) of the individuals worked in paddy fields. Almost all had acute fever (98.8%), myalgia (92.9%), and headache (92.7%), but fewer had other related symptoms. Out of the 4,000 individuals, 2,496 (62.4%) underwent a laboratory test; however, the laboratory test results of only 1,445 (57.9%) and the microscopic agglutination results of 41 (2.8%) were available at the sentinel sites. Less than 2% of the reported individuals underwent prophylactic treatment. These findings will help enhance the ongoing efforts for controlling and preventing leptospirosis in Sri Lanka. Sentinel surveillance is a useful tool, but the data quality needs to be improved by supplementing the findings with adequate laboratory diagnosis data.

Between January 2004 and December 2004, an outbreak of imipenem-resistant Acinetobacter baumannii (IRAB) in 2 intensive care units (ICU) of Chosun University Hospital, Korea affected 77 patients. A case-control study revealed that the time spent in the hospital and mechanical ventilation practices were risk factors. IRAB was isolated from the hands of 4% (5/124) of healthcare workers; 27.3% (21/77) of the samples obtained from the ICU environment. A pulsed-field gel electrophoresis analysis showed that 82.1% (23/28) of clinical IRAB isolates and 85.7% (6/7) of environmental IRAB isolates were type A. The ISAba1F/OXA-51-likeR PCR showed that 93.7% (30/32) of IRAB strains had the ISAba1 gene upstream of the bla_OXA-51-like gene. Two ISAba1F/OXA-51-likeR PCR-negative IRAB strains were bla_IMP-1 positive. All of the IRAB strains tested by PCR were negative for bla_VIM, bla_SIM, bla_GIM-1, bla_SPM-1, bla_GES, bla_OXA-23-like, blaOXA-24-like, and bla_OXA-58-like carbapenemase genes. After implementing an infection control strategy, a steady reduction in the attack rate of IRAB infection was observed.

Toxoplasma gondii genotypes were isolated and characterized from cephalic muscle samples collected from 24 goats slaughtered at an abattoir in Okinawa between 2008 and 2009. Of the 24 samples assayed using latex agglutination, 18 were seropositive, 2 were pseudo-positive, and 4 were seronegative against T. gondii antibodies. The samples were then inoculated into laboratory mice to isolate the parasite. Among the isolated samples, 13 (72.2% of the 18 seropositive strains in the latex agglutination assay) were seropositive, 1 (50%) was pseudo-positive, and none were seronegative. However, after being frozen and stored at −20ºC, all samples were found to be T. gondii-free. Of the 14 isolates of the GRA6 genotype, 6 were of type I, 7 were of type II, and 1 was of type III; the genotype distribution ratio was similar to that of T. gondii strains isolated from locally raised pigs. Moreover, no sulfonamid-tolerant dhps gene mutant of T. gondii was detected.

Twenty bacterial strains isolated from the blood of patients with suspected Streptococcus suis infection based on clinical symptoms in northern Thailand between 2009 and 2010 were subjected to phenotypic and genotypic identification. Commercial identification kits and a PCR-based assay targeting the S. suis-specific 16S rDNA sequence correctly identified S. suis isolated from patients in northern Thailand; however, there was a risk of misidentifying S. gallolyticus as S. suis using a PCR assay targeting the S. suis-specific house keeping gene encoding glutamate dehydrogenase. This is the first paper to report S. gallolyticus infection in humans in Thailand.

Reports of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections have recently increased in Japan; however, these studies contain limited information on their epidemiology. We performed a single-center study in the Tokyo Medical University Hospital located in Shinjuku, a central area of Tokyo, Japan. From 2,099 MRSA isolates obtained during July 2007 to March 2009, we selected 44 MRSA isolates with a MIC of <2 μg/mL for imipenem. Among 44 isolates, 28 strains had type IV or type V SCCmec, and we classified them as CA-MRSA. We identified only 1 Panton-Valentine leukocidin (PVL)-positive MRSA strain, which belonged to SCCmec type V. The PVL-positive CA-MRSA strain was isolated from a patient with multiple subcutaneous abscesses. The patient had returned to Japan from India; thus, the strain may have been contracted from outside of Japan. Thirteen (46.4%) and 15 strains (53.6%) were isolated from outpatients and inpatients, respectively. The major sites of infection included the respiratory tract (8 strains, 28.6%), skin/soft tissue (4 strains, 14.3%), and nasal cavity (4 strains, 14.3%). It is important to note that the most common site of CA-MRSA infection in inpatients was the respiratory tract; respiratory infections with CA-MRSA frequently cause severe infectious diseases.

Ascaris roundworm isolates from Japan and central Europe were examined by sequencing analyses to better understand geographically induced nucleotide variation and genotype distribution according to host. Three well-supported clusters (denoted as A, B, C) were identified by generating cox1 sequences of mtDNA from these regions. Among 5 pig isolates collected in eastern Honshu, Japan, in 2010, 3 carried DNA characteristics for cluster A and 2 corresponded with the characteristics of cluster B. The sequence of the human isolate JH1 from north-central Honshu, fixed in formalin since 1972, conformed to the characteristics of cluster A. Differential analysis of ribosomal ITS1 region revealed the JH1 isolate sequence profile of Ascaris lumbricoides. Cluster C, which was the most distinguish cluster, was formed by reference Slovak isolates and has been so far found almost exclusively in European pigs. A fluctuating prevailing distribution of A and B lineages in human and pig hosts in different territories of the world and the global distribution of several haplotypes indicate their establishment before secondary differentiation in a given region due to host affiliation. The protocol established for DNA isolation from formalin-fixed specimens using the modified procedure with the Qiagen extraction set can be used as a tool for retrospective studies in ascarid helminths when only archival specimens are available.