Diseño y evaluación de una reacción de polimerasa en cadena (RPC) múltiple, para la identificación de bacterias causantes de meningitis aguda en líquido cefalorraquídeo de niños chilenos / Multiplex PCR assay in spinal fluid to identify simultaneously bacterial pathogens associated to acute bacterial meningitis in Chilean children

Background: Acute bacterial meningitis (ABM) is a serious disease that needs rapid diagnosis for an accurate treatment. The most important etiological agents are: Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae type b. Overall pathogen detection rate in patients with ABM in Chile is 83 percent. Aim: To evaluate a Polymerase Chain Reaction (PCR) protocol for simultaneous detection of several pathogens in patients with ABM. Material and methods: We designed and evaluated a multiplex PCR protocol for simultaneous specific genes identifications of S pneumoniae (¡ytA and ply genes), N meningitidis (ctrA, crgA) and H influenzae (bexA) in cerebrospinal fluid (CSF) samples from pediatric patients with suspected diagnosis of ABM. Sensitivity, specificity and minimum detection levels of DNA were determined. Amplifications ofrDNA 16S gene was done to confirm extraction of bacterial DNA. Results: Ninety nine CSF samples were studied, 90 from children with fever and negative CSF culture, and 9 from ABM and positive culture patients. The PCR protocol had a sensitivity of 89 percent, specificity of 100 percent, positive predictive value 100 percent and negative predictive value 99 percent. Conclusions: We observed a high concordance (89 percent) between bacteriological cultures and the PCR protocol results. This diagnostic tool could increase identification of agents in specific settings such as patients previously treated with antibiotics.

Cuerpo extraño intravaginal secundario a migración de aguja de osteosíntesis de cadera / Intravaginal foreign body due to migration of needle hip fixation

Se presenta caso clínico de migración de aguja de fijación de artroplastia de cadera a vagina en mujer embarazada.

We report a case of an intravaginal foreign body due to migration of needle hip fixation from hip arthroplasty in a pregnant woman.

Perfil de susceptibilidad a los antimicrobianos en cepas de E coli productoras de Shiga toxina (STEC) aisladas de infecciones humanas y de alimentos / Antimicrobial susceptibility of shiga toxin producing E coli (STEC) strains isolated from human infections and food

BACKGROUND: Shiga toxin-producing E coli (STEC) are zoonotic pathogens associated to sporadic episodes of bloody diarrhea, foodborne outbreaks, and Hemolytic Uremic Syndrome (HUS), with worldwide public health impact. Antibiotic use in STEC infections is controversial because of the potential to increase production and secretion of Shiga toxins. AIM: To study the in vitro antimicrobial susceptibility profile of STEC. MATERIAL AND METHODS: The in vitro susceptibility profile against 10 antimicrobials of STEC strains isolated from 29 meat products, 20 patients with diarrhea and 9 HUS patients was studied. Minimal Inhibitory Concentrations (microg/ml) by agar dilution method for ampicillin, cloramphenicol, ciprofloxacin, amikacin, gentamycin, cotrimoxazol, ceftriaxone, tetracycline, fonsfomycin and azihromycin were measured according to NCCLS recommendations. RESULTS: Strains from patients with diarrhea or HUS were all susceptible to the 10 antimicrobials and only 13.7% had intermediate resistance to cloramphenicol. Strains from meat products had a similar susceptibility profile, with only 3.5% resistance to tetracycline, 3.5% intermediate resistance to cloramphenicol and 7% to fosfomycin. All 58 strains were considered resistant to azithromycin (MIC >32 microg/ml). CONCLUSIONS: Similarity of susceptibility profiles between STEC strains from human and food origin suggests a role of food chain in transmission to humans.