Recent acute reduction in macrolide-resistant Mycoplasma pneumoniae infections among Japanese children.

INTRODUCTION: Mycoplasma pneumoniae contributes to numerous pneumonia cases among children and young adults. Therefore, this study aimed to investigate the prevalence of M. pneumoniae infections among Japanese children, occurring since 2008. METHODS: Nasopharyngeal swab specimens were obtained from all cases, following which real-time PCR was performed to identify M. pneumoniae. Further, the p1 genotypes of isolates were determined using the PCR restriction fragment length polymorphism typing method. RESULTS: The annual rate of macrolide-resistant M. pneumoniae (MRMP) infections peaked at 81.8% in 2012 and decreased annually until 2015. Although the infection rate increased to 65.3% in 2016, it decreased again to 14.3% in 2018. Although >90% of isolates harbored the type 1 genotype until 2012, this rate decreased, and approximately 80% harbored p1 genotypes other than type 1 in 2018. Furthermore, the occurrence rate of MRMP among the type 1 isolates was very high (82.4%), whereas that among p1 genotypes other than type 1 was very low (6.5%). CONCLUSIONS: MRMP occurrence potentially decreased owing to changes in not only antibiotic usage but also in the distribution of p1 genotype among isolates.

Epidemiology of urinary tract infections in children: Causative bacteria and antimicrobial therapy.

BACKGROUND: Urinary tract infections (UTIs) are the most common bacterial infections in children. This study aimed to review characteristics of causative bacteria and the effectiveness of antimicrobial therapy in children with febrile UTIs. METHODS: Clinical records of 108 patients (130 episodes) with febrile UTIs admitted to the Kawasaki Medical School Hospital between July 2009 and October 2016 were retrospectively reviewed. The characteristics of the causative bacteria, antibacterial therapy, and therapeutic effect were verified. RESULTS: Patients were aged between 0 and 183 months (median age: 3 months). Seventy-three (67.6%) were males. Sixty-three episodes (48.5%) were diagnosed with complicated UTIs. Forty-seven episodes (36.2%) were observed in patients aged <3 months; 15 of them had complicated UTIs. Escherichia coli (E. coli) was the most common pathogen, followed by Enterococcus faecalis (E. faecalis). Blood cultures were positive in three episodes. Among the 130 episodes, 62 (47.7%) were treated with a combination of ampicillin and third-generation cephalosporins, followed by third-generation cephalosporins (31 episodes, 23.8%) and sulbactam sodium / ampicillin sodium (15 episodes, 11.5%). In case of patients with uncomplicated/complicated UTIs and patients aged <3 and ≥3 months, the most common pathogen was E. coli, followed by E. faecalis. There was no difference in therapeutic effects between "combination ampicillin and third-generation cephalosporins" and "third-generation cephalosporin monotherapy" administered for the treatment of UTIs caused by E. coli. CONCLUSIONS: Escherichia coli is the most common pathogen among pediatric UTIs. For antibacterial therapy, third-generation cephalosporin monotherapy is effective and may not require combination therapy with ampicillin.

Low prevalence of Chlamydia pneumoniae infections during the Mycoplasma pneumoniae epidemic season: Results of nationwide surveillance in Japan.

OBJECTIVE: Chlamydia pneumoniae and Mycoplasma pneumoniae are both common causes of atypical pneumonia. We conducted an annual national survey of Japanese children to screen them for C. pneumoniae infections during the M. pneumoniae epidemic season. METHODS: Nasopharyngeal swab specimens were collected from children aged 0-15 years with suspected acute lower respiratory tract infection due to atypical pathogens, at 85 medical facilities in Japan from June 2008 to March 2018. Specimens were tested for infection using real-time polymerase chain reaction assays. RESULTS: Of 5002 specimens tested, 1822 (36.5%) were positive for M. pneumoniae alone, 42 (0.8%) were positive for C. pneumoniae alone, and 20 (0.4%) were positive for both organisms. In children with C. pneumoniae infection, the median C. pneumoniae DNA copy number was higher in those with single infections than in those with M. pneumoniae coinfection (p = 0.08); however it did not differ significantly according to whether the children had received antibiotics prior to sample collection (p = 0.34). CONCLUSIONS: The prevalence of C. pneumoniae infection was substantially lower than that of M. pneumoniae infection during the study period. The change in prevalence of C. pneumoniae was not influenced by that of M. pneumoniae. Children with single C. pneumoniae infection are likely to have had C. pneumoniae infection, while those with coinfection are likely to have been C. pneumoniae carriers.

Comparing Antimicrobial Susceptibilities among Mycoplasma pneumoniae Isolates from Pediatric Patients in Japan between Two Recent Epidemic Periods.

We compared the antimicrobial susceptibility of Mycoplasma pneumoniae isolates from pediatric patients in Japan in 2011-2012 and 2015-2016, when epidemics occurred. The antimicrobial activity of macrolides and tetracyclines against M. pneumoniae infection tended to be restored in 2015-2016. There was no change in the antimicrobial activity of quinolones against M. pneumoniae infection.

Incidence of Viremia With DNA Viruses in Oncology Patients With Febrile Neutropenia.

BACKGROUND: Although febrile neutropenia (FN) is one of the most common adverse events produced by chemotherapy, its microbiological etiology is determined for only 15% to 30% of cases. OBJECTIVES: We investigated the rate of viremia with common DNA viruses in patients with FN. STUDY DESIGN: From June 2012 to April 2014, 72 blood samples from 24 patients receiving chemotherapy, who experienced FN episodes, were examined for the presence of herpes viruses and other DNA viruses. We used real-time polymerase chain reaction assays to detect herpes simplex virus type 1 and 2, varicella zoster virus, Epstein-Barr virus, cytomegalovirus, human herpes virus types 6 and 7, BK virus and human parvovirus B19 (B19). RESULTS: Viruses were identified in 14 of 72 samples (19.4%). The detected etiological agents were BK virus (5 episodes), human herpes virus type 6 (4 episodes), B19 (4 episodes), Epstein-Barr virus (2 episodes), and cytomegalovirus (1 episode). CONCLUSIONS: Our results indicate that viral infections are common causes in patients with FN. Therefore, viruses may be responsible for FN in a large proportion of patients in whom a causative microorganism could not be identified, and this viral etiology may explain their poor response to antibiotic therapy.

Macrolide-Resistant Mycoplasma pneumoniae Infection, Japan, 2008-2015.

We evaluated isolates obtained from children with Mycoplasma pneumoniae infection throughout Japan during 2008-2015. The highest prevalence of macrolide-resistant M. pneumoniae was 81.6% in 2012, followed by 59.3% in 2014 and 43.6% in 2015. The prevalence of macrolide-resistant M. pneumoniae among children in Japan has decreased.

[Hypnotic effects of ramelteon during electroencephalography].

OBJECTIVE: The efficacy of ramelteon, a sleep agent thought to induce natural sleep through its actions on the melatonin receptors 1 and 2, was evaluated during electroencephalography (EEG). METHODS: We retrospectively analyzed the data from 862 EEG sessions in the electronic medical records of 523 patients (mean age, 8.9 ± 6.4 years; range, 0-38 years) who underwent EEGs in the Department of Pediatrics of Kawasaki Medical School Hospital. We compared the sleep induction statuses of patients not treated with hypnotics and those treated with the following hypnotics: ramelteon, triclofos sodium, and/or chloral hydrate. RESULTS: The success rates of sleep induction in the different groups were as follows: 440/513 (85.7%) in the hypnotic-free, 60/63 (95.2%) in the ramelteon, 209/217 (96.3%) in the triclofos sodium, 36/37 (97.3%) in the chloral hydrate, and 29/32 (90.6%) in the triclofos sodium plus chloral hydrate group. The incidence of adverse reactions was 0/63 (0%) in the ramelteon, 104/199 (52.2%) in the triclofos sodium, 12/31 (38.7%) in the chloral hydrate, and 20/30 (66.7%) in the triclofos sodium plus chloral hydrate group. The mean sleep latency in the ramelteon group was 22.3 ± 12.8 min (range, 5-60 min). CONCLUSIONS: Ramelteon induced sleep significantly more compared to the control group. The incidence of adverse reactions after treatment with ramelteon was significantly lower than after treatment with any of the other hypnotics. These results suggest that ramelteon is useful as a hypnotic during EEG.