Central venous catheter-related infections caused by Corynebacterium amycolatum and other multiresistant non-diphtherial corynebacteria in paediatric oncology patients

ABSTRACT Bloodstream and venous catheter-related corynebacterial infections in paediatric patients with haematological cancer were investigated from January 2003 to December 2014 at the Brazilian National Cancer Institute in Rio de Janeiro, Brazil. We observed that during cancer treatment, invasive corynebacterial infections occurred independent of certain factors, such as age and gender, underlying diseases and neutropenia. These infections were ssscaused by Corynebacterium amycolatum and other non-diphtherial corynebacteria. All cases presented a variable profile of susceptibility to antimicrobial agents, except to vancomycin. Targeted antibiotic therapy may contribute to catheters maintenance and support quality of treatment. Non-diphtherial corynebacteria must be recognized as agents associated with venous access infections. Our data highlight the need for the accurate identification of corynebacteria species, as well as antimicrobial susceptibility testing.

Genome sequence of a multidrug-resistant Corynebacterium striatum isolated from bloodstream infection from a nosocomial outbreak in Rio de Janeiro, Brazil

Multidrug-resistant (MDR) Corynebacterium striatum has been cited with increased frequency as pathogen of nosocomial infections. In this study, we report the draft genome of a C. striatum isolated from a patient with bloodstream infection in a hospital of Rio de Janeiro, Brazil. The isolate presented susceptibility only to tetracycline, vancomycin and linezolid. The detection of various antibiotic resistance genes is fully consistent with previously observed multidrug-resistant pattern in Corynebacterium spp. A large part of the pTP10 plasmid of MDR C. striatum M82B is present in the genome of our isolate. A SpaDEF cluster and seven arrays of CRISPR-Cas were found.

Biofilm production by multiresistant Corynebacterium striatum associated with nosocomial outbreak

Corynebacterium striatum is a potentially pathogenic microorganism that causes nosocomial outbreaks. However, little is known about its virulence factors that may contribute to healthcare-associated infections (HAIs). We investigated the biofilm production on abiotic surfaces of multidrug-resistant (MDR) and multidrug-susceptible (MDS) strains of C. striatum of pulsed-field gel electrophoresis types I-MDR, II-MDR, III-MDS and IV-MDS isolated during a nosocomial outbreak in Rio de Janeiro, Brazil. The results showed that C. striatum was able to adhere to hydrophilic and hydrophobic abiotic surfaces. The C. striatum 1987/I-MDR strain, predominantly isolated from patients undergoing endotracheal intubation procedures, showed the greatest ability to adhere to all surfaces. C. striatum bound fibrinogen to its surface, which contributed to biofilm formation. Scanning electron microscopy showed the production of mature biofilms on polyurethane catheters by all pulsotypes. In conclusion, biofilm production may contribute to the establishment of HAIs caused by C. striatum.

Aspectos fenotípicos e do potencial patogênico de amostra de Corynebacterium diphtheriae isolada de processo de osteomielite em paciente com neoplasia / Phenotypic aspects and pathogenic potential of Corynebacterium diphtheriae strains isolated from cancer patient with osteomyelitis

Além da difteria permanecer endêmica em diversos países, os clínicos e microbiologistas também devem permanecer atentos ao fato de amostras atoxinogênicas de Corynebacterium diphtheriae causarem infecções invasivas, inclusive em pacientesimunocomprometidos e/ou hospitalizados. Um grupo de microrganismos, incluindo C. diphtheriae, tem sido relacionado com quadros de osteomielite. Em casos de câncer, pode ser favorecido o aparecimento de quadros de osteomielite em decorrência de contaminação por via hematogênica, foco infeccioso ou lesão contígua ao osso. Entretanto, ainda são poucas as investigações relativas ao potencial patogênico de cepas atoxinogênicas de C. diphtheriae. No presente estudo, foi descrito o primeiro caso de isolamento de C.diphtheriae subsp. mitis atoxinogênico e do biotipo não fermentador de sacarose (BR5015) de osteomielite em paciente com câncer.O microrganismo foi capaz de expressar os seguintes fatores de virulência: expressão de perfil de aderência misto dos tipos agregativo e difuso (AA-AD) e elevada (11,13%) capacidade de sobrevivência intracitoplasmática em células epiteliais humanas (HEp-2) além da produção de porfirina e de enzimas catalase, nitrato redutase e DNAse. C. diphtheriae atoxinogênico não deve serconsiderado como mero contaminante, uma vez que pode estar direta ou indiretamente relacionado com o estabelecimento e/ou manutenção de processos infecciosos de origens diversas, incluindo osteomielite.

As well diphtheria remaining endemic in several countries, clinicians and microbiologists must also remain alert to the fact that nontoxigenic samples of Corynebacterium diphtheriae are capable of causing invasive infections, especially in hospitalized and/or immunocompromised patients. Patients with cancer are more susceptible to the appearance of cases of osteomyelitisobtained by hematogenic contamination, an infectious focus or by lesions adjacent to bone. Many microorganisms may be related to cases of osteomyelitis, including C. diphtheriae. However, there are still only a low number of investigations into the pathogenic potential of nontoxigenic strains of C. diphtheriae. The present study is the first documented case of isolation of a nontoxigenic C.diphtheriae subsp. mitis of the non sucrose-fermenting biotype (BR5015 strain) from osteomyelitis in the frontal bone of a patient with adenoid cystic carcinoma. The virulence factors tests were as follows: expression of a mixed adherence patterns of aggregativediffuse(AA-DA) types; high (11.13%) ability to survive within HEp-2 cells; DNase, catalase, nitrate-reductase activities. Therefore, nontoxigenic C. diphtheriae should not be merely regarded as a contaminant, since it can be directly or indirectly related to the establishment and/or maintenance of infectious processes, including osteomyelitis.

Antimicrobial activity of calcium hydroxide pastes on Enterococcus faecalis cultivated in Root Canal Systems

The effectiveness of calcium hydroxide pastes: Calen™ and PMCC-Calen™ associated to chemo-mechanical preparation was assessed on Enterococcus faecalis grown within root canals. Seventy incisors were inserted into TSB medium, sterilized and contaminated with E. faecalis. Culture medium was replaced each 24 h and incubated at 37oC for 72 h. After chemo-mechanical preparation, root canals were filled with Calen™ or PMCC-Calen™ (7 or 14 days). Pastes were removed and teeth were inserted into test tubes containing Enterococcosel broth. Calen™ paste (maintained for 7 and 14 days) induced 70 percent elimination of enterococci and PMCC-Calen™ 100 percent elimination only after maintenance for 14 days. These medications were significantly more effective (p<0.001) than chemo-mechanical protocol alone and PMCC-Calen™ maintained for 7 days, both incapable to eliminate the viability of enterococci. Calcium hydroxide pastes demonstrated important adjuvant effects in the elimination of enterococci during chemo-mechanical preparation of root canal systems. When associated with PMCC, calcium hydroxide pastes should be maintained for at least 14 days.

A eficácia das pastas de hidróxido de cálcio: Calen® e Calen-PMCC® associadas ao preparo químico-mecânico, foi avaliada sobre Enterococcus faecalis cultivados no interior dos canais radiculares. Setenta incisivos foram inseridos em caldo TSB, esterilizados e contaminados com E. faecalis. O meio de cultivo foi substituído a cada 24 h, sendo incubados a 37oC por 72 h. Após o preparo químico-mecânico, os canais radiculares foram preenchidos com Calen® ou Calen-PMCC® (7 ou 14 dias). As pastas foram removidas e os dentes inseridos em tubos contendo caldo Enterococcosel. A pasta Calen® (mantida por 7 ou 14 dias) induziu a eliminação dos enterococos em 70 por cento dos dentes, enquanto a pasta Calen-PMCC® induziu a eliminação em 100 por cento dos dentes, somente após a manutenção por 14 dias. Tais medicações foram significativamente mais efetivas (p<0,001) do que o protocolo do preparo químico-mecânico e o Calen-PMCC® mantido por 7 dias, ambos incapazes de eliminar os enterococos. As pastas de hidróxido de cálcio demonstraram efeitos adjuvantes importantes na eliminação dos enterococos durante o preparo químico-mecânico dos sistemas de canais radiculares. Quando associada ao PMCC, as pastas de hidróxido de cálcio devem ser mantidas por pelo menos 14 dias.

Nocardiosis: an overview and additional report of 28 cases in cattle and dogs / Nocardiose: visão geral e relato de 28 casos em vacas e cães

Phenotypic characteristics, antimicrobial susceptibility profile, and clinical-epidemiological features of 28 Nocardia strains isolated from 19 cases of bovine mastitis, eight cutaneous-subcutaneous lesions and one case of pneumonia in dogs were evaluated. Microbiological, biochemical, cytological and scanning electron microscopy methods were used in diagnosis. Nocardia asteroides type IV, Nocardia otitidiscaviarum,Nocardia nova (type III) and Nocardia farcinica (type V) were isolated from bovine milk, bronchial lavage and/or cutaneous-subcutaneous abscesses in dogs. Nocardial bovine mastitis was diagnosed predominantly in clinical cases, in dairy herds with poor environmental hygienic conditions between milking and inappropriate intramammary therapy. Canine nocardiosis was observed commonly in animals co-infected with distemper virus. Sulphamethoxazole-trimethoprim (92.8 percent), amikacin (92.8 percent) and ceftiofur (92.8 percent) were the most effective drugs in 28 isolates. Multiple drug resistance to three or more and five or more antimicrobials was observed in ten (35.7 percent) and three (10.7 percent) strains, respectively, predominantly with use of cloxaxillin, cefoperazone and ampicillin. The species (type) classification, clinical-epidemiological characteristics, diagnosis, multiple-drug resistance and public health considerations in Nocardia strains isolated from cattle and dogs in Brazil are discussed, with special reference to report of bovine mastitis by N. otitidiscaviarum by first time in Brazil and the similarity between Nocardia species isolated from human and animal origin.

A caracterização fenotípica, perfil de sensibilidade aos antimicrobianos e aspectos clínico-epidemiológicos foram avaliados em 28 linhagens de Nocardia isoladas de 19 casos de mastite, oito lesões tegumentares e um caso de pneumonia em cão. Foram utilizados no diagnóstico métodos microbiológicos, bioquímicos, citológicos e microscopia eletrônica de varredura. Nocardia asteroides tipo IV, N. otitidiscaviarum,N. nova (tipo III) e N. farcinica (tipo V) foram isoladas do leite de vacas com mastite, de material de lavado transtraqueal e de lesões cutâneas de cães. Nocardiose mamária bovina foi diagnosticada predominantemente sob a forma clínica, em propriedades com precárias condições de higiene na pré e pós-ordenha, e inadequado procedimento de terapia intramamária. Nocardiose canina foi diagnosticada comumente em animais co-infectados com o vírus da cinomose. Sulfametoxazole/trimetoprim (92,8 por cento), amicacina (92,8 por cento) e ceftiofur (92,8 por cento) foram os antimicrobianos mais efetivos frente às linhagens de Nocardia. Resistência múltipla a três ou mais e cinco ou mais antimicrobianos foram observadas, respectivamente, em dez (35,7 por cento) e três (10,7 por cento) linhagens, notadamente frente à cloxacilina, cefoperazona e ampicilina. A caracterização de espécies (tipo), aspectos clínico-epidemiológicos, diagnóstico, resistência múltipla aos antimicrobianos e reflexos em saúde pública de linhagens de Nocardia isoladas de bovinos e cães no Brasil foram discutidos. Foi destacada a similaridade entre as espécies de Nocardia isoladas de animais e do homem, e a primeira descrição no Brasil de N. otitidiscaviarum na etiologia da mastite bovina.