Genomic insights of international clones of Haemophilus influenzae causing invasive infections in vaccinated and unvaccinated infants.

The emergence of invasive Haemophilus influenzae infections in vaccinated patient is a public health concern. We have investigated the genomic basis of invasiveness and possible vaccine failure in H. influenzae causing invasive disease in vaccinated and unvaccinated children in Brazil. Three H. influenzae strains isolated from blood cultures of pediatric patients were sequenced. Serotype, MLST, resistome and virulome were predicted using bioinformatic tools, whereas single nucleotide polymorphisms (SNPs) analysis of cap loci and the presence of the putative virulence-enhancing IS1016-bexA partial deletion were predicted in silico. Infections were caused by H. influenzae type a (Hia), type b (Hib) and nontypeable (NTHi), belonging to international high-risk clones of sequence types ST23, ST6 and ST368, respectively, which have been identified in North American, European and Asian countries. Convergence of ampicillin resistance and virulence in Hib-ST6 was supported by blaTEM-1B and deletion in the bexA gene, whereas presence of SNPs in the cap-b locus was associated with antigenic modifications of the capsule structure. Hia-ST23 and NTHi-ST368 strains carried galU, lpsA, opsX, rfaF, iga1, lgtC and lic1/lic2 virulence genes, associated with colonization, adaptation and damage to the lung, or invasiveness. In summary, deletion in the bexA gene and presence of SNPs in the cap locus of Hib could be contributing to invasive disease and possible vaccine failure in pediatric patients, whereas serotype replacement of Hib with type "a" and NTHi strains denotes the ability of non-vaccine serotypes to re-colonize vaccinated patients. Finally, the dissemination of international high-risk clones of H. influenzae emphasizes the importance of monitoring changes in the molecular epidemiology of invasive H. influenzae disease.

Outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in an intermediate-risk neonatal unit linked to onychomycosis in a healthcare worker.

OBJECTIVE: To describe an outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in an intermediate-risk neonatal unit. METHODS: After the identification of the first cases, the situation was regarded as an outbreak, and basic preventive measures against nosocomial infections were strictly enforced, and possible sources of dissemination were investigated. RESULTS: The outbreak lasted for 6 months and affected 36 newborn infants, causing seven infections and 29 colonizations. In the first stage of the outbreak, patients developed infection, but in the second stage, they were asymptomatic and were only identified by surveillance cultures. The outbreak was controlled after the identification and treatment of the healthcare worker who had been diagnosed with onychomycosis and whose hands were contaminated with extended-spectrum beta-lactamase-producing Klebsiella pneumoniae. CONCLUSIONS: The detection and control of occult dissemination of this multiresistant bacterium among low-risk newborn infants prevented its endemic dissemination in the neonatal unit, as well as the exposure of critically ill and susceptible patients to the infection.

Outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in an intermediate-risk neonatal unit linked to onychomycosis in a healthcare worker

OBJETIVO: Descrever surto por Klebsiella pneumoniae produtora de beta-lactamase de espectro estendido em berçário de risco intermediário. MÉTODOS: Após identificação dos primeiros casos, a situação foi conduzida como surto, sendo intensificadas as medidas básicas de prevenção de infecções hospitalares e investigadas possíveis fontes de disseminação da bactéria. RESULTADOS: O surto durou 6 meses e atingiu 36 recém-nascidos, causando sete infecções e 29 colonizações. Na primeira fase do surto, os portadores evoluíram com infecção, porém, na segunda fase, os portadores eram assintomáticos e só foram identificados por culturas de vigilância. O surto foi resolvido após identificação e tratamento de profissional de saúde que apresentava onicomicose e era portadora de Klebsiella pneumoniae produtora de beta-lactamase de espectro estendido nas mãos. CONCLUSÃO: Detecção e controle da disseminação oculta da bactéria multirresistente entre os recém-nascidos de menor risco evitou sua instalação endêmica no berçário, bem como a conseqüente exposição dos pacientes mais graves e suscetíveis à infecção.

OBJECTIVE: To describe an outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in an intermediate-risk neonatal unit. METHODS: After the identification of the first cases, the situation was regarded as an outbreak, and basic preventive measures against nosocomial infections were strictly enforced, and possible sources of dissemination were investigated. RESULTS: The outbreak lasted for 6 months and affected 36 newborn infants, causing seven infections and 29 colonizations. In the first stage of the outbreak, patients developed infection, but in the second stage, they were asymptomatic and were only identified by surveillance cultures. The outbreak was controlled after the identification and treatment of the healthcare worker who had been diagnosed with onychomycosis and whose hands were contaminated with extended-spectrum beta-lactamase-producing Klebsiella pneumoniae. CONCLUSION: The detection and control of occult dissemination of this multiresistant bacterium among low-risk newborn infants prevented its endemic dissemination in the neonatal unit, as well as the exposure of critically ill and susceptible patients to the infection.