Pediatric hypervirulent Klebsiella pneumoniae septic arthritis.

Cases of infection with hypervirulent Klebsiella pneumoniae are gradually increasing in number, and cause life-threatening community-acquired infection even in immunocompetent patients. A 14-year-old boy developed septic hip arthritis due to hypervirulent K. pneumoniae (sequence type 23, serotype K1, magA positive). The patient initially seemed to have been successfully treated with antibiotics and surgical intervention, but septic arthritis developed into osteomyelitis of the femoral head and myositis, which required long-term antibiotic therapy and additional surgical intervention. This is the first pediatric case of hypervirulent K. pneumoniae septic hip arthritis. Treatment plans should mainly consist of antibiotic therapy and surgical intervention. Clinicians, even pediatricians, in developed countries should be aware of the increasing incidence of hypervirulent Klebsiella pneumoniae infection.

Molecular epidemiologic study of community-associated methicillin-resistant Staphylococcus aureus with Panton-Valentine leukocidin gene among family members in Japan.

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is one of the worldwide concerns of antimicrobial chemotherapy. An accumulation of ten patients in five families (A-E) suffering from skin and soft tissue infection (SSTI) of CA-MRSA was experienced in 2012, in Fuchu-shi, Tokyo, Japan. Molecular epidemiological investigation was performed for the 10 MRSA strains obtained from 8 children and 2 of their parents to assess endemic patterns of CA-MRSA in the community. Results of molecular typing, presence of toxin genes and antimicrobial susceptibilities were analyzed combined with the patients' clinical information. Each family had its own unique MRSA strain: A, ST30-SCCmec IVd; B, ST8-SCCmec IVd; C, ST8-SCCmec IVa; D, ST8-SCCmec IVl; E, ST8-SCCmec IVl and ST858-SCCmec IVl. Seven strains from the families A-C carried Panton-Valentine leukocidin gene. Three strains from the families D and E carried toxic shock syndrome toxin gene. Strains belonged to the same family demonstrated genetically related banding patterns of pulsed-filed gel electrophoresis. The family C experienced intrafamilial transmission of USA300-0114. Our data showed the MRSA clones disseminating in this community were highly diverse. They contained USA300-0114 clone, the rapidly distributing clone in the world, as well as MRSA clones identified in Japan. Our results suggested intrafamilial transmission of MRSA could be initial phenomenon of wide transmission in a community, therefore CA-MRSA SSTI in children and their family members should be monitored closely in order to notice the spread of highly pathogenic and transmittable strains.

Rapid and accurate identification of human-associated staphylococci by use of multiplex PCR.

Although staphylococci are identified by phenotypic analysis in many clinical laboratories, these results are often incorrect because of phenotypic variation. Genetic analysis is necessary for definitive species identification. In the present study, we developed a simple multiplex-PCR (M-PCR) for species identification of human-associated staphylococci, which were as follows: Staphylococcus aureus, S. capitis, S. caprae, S. epidermidis, S. haemolyticus, S. hominis, S. lugdunensis, S. saprophyticus, and S. warneri. This method was designed on the basis of nucleotide sequences of the thermonuclease (nuc) genes that were universally conserved in staphylococci except the S. sciuri group and showed moderate sequence diversity. In order to validate this assay, 361 staphylococcal strains were studied, which had been identified at the species levels by sequence analysis of the hsp60 genes. In consequence, M-PCR demonstrated a sensitivity of 100% and a specificity of 100%. By virtue of simplicity and accuracy, this method will be useful in clinical research.

Multiplex-PCR method for species identification of coagulase-positive staphylococci.

In veterinary medicine, coagulase-positive staphylococci (CoPS) other than Staphylococcus aureus have frequently been misidentified as being S. aureus strains, as they have several phenotypic traits in common. There has been no reliable method to distinguish among CoPS species in veterinary clinical laboratories. In the present study, we sequenced the thermonuclease (nuc) genes of staphylococcal species and devised a multiplex-PCR (M-PCR) method for species identification of CoPS by targeting the nuc gene locus. To evaluate sensitivity and specificity, we used this M-PCR method on 374 staphylococcal strains that had been previously identified to the species level by an hsp60 sequencing approach. We could successfully distinguish between S. aureus, S. hyicus, S. schleiferi, S. intermedius, S. pseudintermedius, and S. delphini groups A and B. The present method was both sensitive (99.8%) and specific (100%). Our M-PCR assay will allow the routine species identification of CoPS isolates from various animal species for clinical veterinary diagnosis.

[A case of bacterial meningitis due to Streptococcus bovis in an infant with normal cerebrospinal fluid findings at the first CSF examination].

Streptococcus bovis very occasionally causes rarely sepsis, endocarditis, and meningitis in newborns and the elderly. We report the case of infant meningitis caused by S. bovis despite normal cerebrospinal fluid (CSF) findings at the first CSF examination. A 77-day-old boy with 21-trisomy and patent foramen ovale and seen for a high fever underwent blood examination and lumbar puncture due to toxic appearance despite a lack of meningeal signs, and was admitted. His CSF findings were normal and he was given intravenous ceftriaxone against potential bacteremia. He had systemic seizures with continuous fever for 2 days after admission and a second CSF examination. Gram-positive coccus grew from his CSF at the first examination, and CSF cells from the second lumbar puncture increased to 4060/tL (86% neutrophils), so vancomycin was added against potential enterococcal meningitis. S. bovis was finally grown from the first CSF, ceftriaxone discontinued, and intravenous ampicillin added. He recovered after 20 days of antibiotic administration. S. bovis becomes a potential pathogen for meningitis in infants, and must be considered as a cause of meningitis despite its very rarity. CSF findings at the first lumbar puncture may be normal for meningitis in newborns and infants at the first CSF examination, so we must be very careful in the diagnosis of bacterial meningitis even with normal CSF findings, and considered antibiotic treatment against potential bacterial meningitis.