Clinical Significance of Isolates Known to Be Blood Culture Contaminants in Pediatric Patients.

Background and objectives: The objective of this study was to investigate the clinical significance of isolates from blood stream infection known to be blood culture contaminants in pediatric patients. Materials and Methods: Microbiological reports and medical records of all blood culture tests issued from 2002 to 2012 (n = 76,331) were retrospectively reviewed. Evaluation for potential contaminants were done by reviewing medical records of patients with the following isolates: coagulase-negative Staphylococcus, viridans group Streptococcus, Bacillus, Corynebacterium, Micrococcus, Aerococcus, and Proprionibacterium species. Repeated cultures with same isolates were considered as a single case. Cases were evaluated for their status as a pathogen. Results: Coagulase-negative Staphylococcus had clinical significance in 23.8% of all cases. Its rate of being a true pathogen was particularly high in patients with malignancy (43.7%). Viridans group Streptococcus showed clinical significance in 46.2% of all cases. Its rate of being a true pathogen was similar regardless of the underlying morbidity of the patient. The rate of being a true pathogens for remaining isolates was 27.7% for Bacillus and 19.0% for Corynebacterium species. Conclusions: Coagulase-negative Staphylococcus and viridans group Streptococcus isolates showed high probability of being true pathogens in the pediatric population, especially in patients with underlying malignancy.

Micrococcus aloeverae - A Rare Cause of Peritoneal Dialysis-Related Peritonitis Confirmed by 16S rRNA Gene Sequencing.

The number of patients receiving peritoneal dialysis has increased worldwide. Herein, we report the first case to our knowledge of continuous ambulatory peritoneal dialysis (CAPD) peritonitis caused by Micrococcus aloeverae, which was initially reported to be caused by Micrococcus luteus in the dialysate culture report but later identified by 16S ribosomal ribonucleic acid (rRNA) gene sequencing as M. aloeverae. A 59-year-old woman visited the emergency room due to abdominal pain. She was hospitalized with CAPD peritonitis. The patient initially responded to empirical antibiotic treatment comprising intraperitoneal cefazolin (15 mg/kg/day) and ceftazidime (1 g/day); however, the leukocyte count of dialysate effluent increased again. M. luteus was isolated four times from peritoneal dialysate cultures. We treated the patient with intraperitoneal administration of vancomycin (2 g loading, followed by 1 g every 7 days) but needed to switch from CAPD to temporary hemodialysis. We analyzed the 16S rRNA sequence to confirm the exact causative organism, and the results revealed that the organism was M. aloeverae. Because M. aloeverae and M. luteus have sequence similarity, 16S rRNA sequencing is a useful method to distingush them.

Molecular characterization of a crustin-like antimicrobial peptide in the giant tiger shrimp, Penaeus monodon, and its expression profile in response to various immunostimulants and challenge with WSSV.

A crustin-like antimicrobial peptide from the haemocytes of giant tiger shrimp, Penaeus monodon was partially characterized at the molecular level and phylogenetic analysis was performed. The partial coding sequence of 299 bp and 91 deduced amino acid residues possessed conserved cysteine residues characteristic of the shrimp crustins. Phylogenetic tree and sequence comparison clearly confirmed divergence of this crustin-like AMP from other shrimp crustins. The differential expression of the crustin-like AMP in P. monodon in response to the administration of various immunostimulants viz., two marine yeasts (Candida haemulonii S27 and Candida sake S165) and two ß-glucan isolates (extracted from C. haemulonii S27 and C. sake S165) were noted during the study. Responses to the application of two gram-positive probiotic bacteria (Bacillus MCCB101 and Micrococcus MCCB104) were also observed. The immune profile was recorded pre- and post-challenge white spot syndrome virus (WSSV) by semi-quantitative RT-PCR. Expressions of seven WSSV genes were also observed for studying the intensity of viral infection in the experimental animals. The crustin-like AMP was found to be constitutively expressed in the animal and a significant down-regulation could be noted post-challenge WSSV. Remarkable down-regulation of the gene was observed in the immunostimulant fed animals pre-challenge followed by a significant up-regulation post-challenge WSSV. Tissue-wise expression of crustin-like AMP on administration of C. haemulonii and Bacillus showed maximum transcripts in gill and intestine. The marine yeast, C. haemulonii and the probiotic bacteria, Bacillus were found to enhance the production of crustin-like AMP and confer significant protection to P. monodon against WSSV infection.

Comparison of antibacterial activity in the hemolymph of marine bivalves from Galicia (NW Spain).

A screening study of in vitro antibacterial activity was conducted in marine bivalves with economical importance and widespread along the coast of Galicia (NW Spain). Hemocyte lysate supernatant (HLS) and plasma of Mytilus galloprovincialis, Ostrea edulis, Crassostrea gigas, Ruditapes decussatus, Ruditapes philippinarum, and Cerastoderma edule were incubated with Vibrio splendidus and Micrococcus sp. HLS and plasma for all the species demonstrated antibacterial activity, and C. edule had the highest activity per unit of protein in these hemolymph fractions. Significant differences were not found between HLS and plasma activities. Furthermore, antibacterial activity against Micrococcus sp. (Gram-positive) was stronger than against V. splendidus (Gram-negative).

A Dorsal homolog (FcDorsal) in the Chinese shrimp Fenneropenaeus chinensis is responsive to both bacteria and WSSV challenge.

Rel/NFkappaB is a family of transcription factors. In the present study, a Rel/NFkappaB family member, Dorsal homolog (FcDorsal) was cloned from the Chinese shrimp Fenneropenaeus chinensis. The full length cDNA of FcDorsal consists of 1627bp, revealed a 1071bp open reading frame encoding 357 aa. The predicted molecular weight (MW) of the deduced amino acid sequence of FcDorsal was 39.78kDa, and its theoretical pI was 8.85. Amino acid sequence analysis showed that FcDorsal contains a Rel homolog domain (RHD) and an IPT/TIG (Ig-like, plexins and transcriptions factors) domain. The signature sequence of dorsal protein existed in the deduced amino acid sequence. Spatial expression profiles showed that FcDorsal had the highest expression level in the hemocytes and lymphoid organ (Oka). The expression profiles in the hemocytes and lymphoid organ were apparently modulated when shrimp were stimulated by bacteria or WSSV. Both Gram-positive (G(+)) bacteria (Micrococcus lysodeikticus) and Gram-negative (G(-)) bacteria (Vibrio anguillarium) injection to shrimp caused the up-regulation of FcDorsal at the transcription level. DsRNA approach was used to study the function of FcDorsal and the data showed that FcDorsal was related to the transcription of Penaeidin 5 in shrimp. The present data provide clues that FcDorsal might play potential important roles in the innate immunity of shrimp. Through comparison of the expression profiles between FcDorsal and another identified Rel/NFkappaB member (FcRelish) in shrimp responsive to WSSV challenge, we speculate that FcDorsal and FcRelish might play different roles in shrimp immunity.

Functional differential immune responses of Mytilus galloprovincialis to bacterial challenge.

Bivalves are filter-feeders that can accumulate large numbers of bacteria, in particular Vibrio species; these can persist within bivalve tissues largely depending on their sensitivity to the hemolymph bactericidal activity. In this work, functional parameters of the hemolymph of Mytilus galloprovincialis were evaluated in response to in vivo challenge with different bacteria (Gram(-) Vibrio anguillarum and V. splendidus, Gram+ Micrococcus lysodeikticus). Mussels were injected with heat-killed bacteria or PBS-NaCl (controls) and hemolymph sampled from 3 to 48 h post-injection (p.i.). In hemocytes, all bacteria induced significant lysosomal membrane destabilisation (LMS) from 3 h p.i. with V. splendidus >V. anguillarum >M. lysodeikticus. LMS showed recovery for both M. lysodeikticus and V. anguillarum, whereas a further time-dependent decrease was observed for V. splendidus. Bacterial challenge also induced a rapid (from 3 h p.i.) and significant increase in serum lysozyme activity; the effect was persistent with M. lysodeikticus and transient for the two Vibrio species. In order to evaluate whether in vivo challenge may affect the subsequent capacity of hemolymph to kill bacteria, the bactericidal activity was tested in an in vitro assay towards E. coli. At 48 h. p.i. hemolymph samples from V. anguillarum-injected mussels showed a significant increase in E. coli killing (+35% with respect to controls); a smaller effect was observed with V. splendidus-injected mussels (+16%), whereas M. lysodeikticus was ineffective. Moreover, hemolymph from V. anguillarum-injected mussels showed an in vitro bactericidal activity towards V. anguillarum 2-folds higher than that of controls. Changes in total hemocyte counts (THC) and in hemocyte populations were evaluated by Flow cytometry at 6 and 48 h p.i., indicating a decrease in THC followed by recovery with all bacteria. Moreover, at 6 h p.i. a general decrease in the percentage of granulocytes was observed (V. splendidus >V. anguillarum >M. lysodeikticus), followed by complete and partial recovery with M. lysodeikticus and V. anguillarum, respectively, but not with V. splendidus. The results demonstrate the existence of differential functional immune responses in M. galloprovincialis to different bacteria.

Micrococcus sedentarius bacteraemia presenting with haemophagocytic syndrome in previously healthy boy.

Haemophagocytic syndromes are the clinical manifestation of an increased macrophagic activity with haemophagocytosis. Infection-associated HS was originally described by Risdall in 1979, in viral disease. Since the initial description HS has also been documented in patients with bacterial, parasitic or fungal infections. We describe a case of Micrococcus sedentarius bacteraemia in a previously healthy 10-y-old boy with haemophagocytic syndrome. Species of micrococci are generally considered as non-pathogenic commensals that colonize the skin, mucosae and oropharynx. We report the first case of Microccoccus sedentarius bacteraemia in an immunocompetent host and first case of HS associated with Micrococcus species.

Hiperqueratosis acral focal asociada a queratolisis punteada / Focal acral hyperkeratosis associated with pitted keratolysis

La hiperqueratosis acral focal se caracteriza por el mismo aspecto clínico que la acroqueratoelastoidosis, pero sin anormalidades en las fibras elásticas. Presentamos el caso de una mujer con dermatosis localizada en palmas, plantas y dorso de articulaciones metacarpofalángicas, de 10 años de evolución, constituida por múltiples pápulas poligonales e hiperhidrosis asociadas, clínicamente compatibles con acroqueratoelastoidosis. Tenía el antecedente de enfermedad en el padre. Además, la paciente presentaba queratolisis punteada palmoplantar. Además, la paciente presentaba queratolisis punteada palmoplantar. El estudio histopatológico descartó elastorrexis y la queratolisis punteada se corroboró por el aspecto clínico y la presencia de elementos cocoides en la capa córnea, evidentes con tinción de PAS. En nuestra opinión, la hiperqueratosis acral focal no constituye una entidad independiente de la acroqueratoelastoidosis

Focal acral hyperkeratosis is characterized by the same clinical appearance as acrokeratoelastoidosis, but without abnormalities in the elastic fibers. We present the case of a woman with a 10-year case of dermatosis localized on the palms, soles and dorsum of the metacarpophalangeal joints, consisting of multiple polygonal papules and associated hyperhydrosis, clinically compatible with acrokeratoelastoidosis. Her father had a history of the disease. In addition, the patient presented with palmoplantar pitted keratolysis. The histopathological study ruled out elastorrhexis, and the pitted keratolysis was corroborated by the clinical appearance and the presence of coccoid elements in the stratum corneum, evident with a PAS stain. In our opinion, the focal acral hyperkeratosis is not a separate entity from the acrokeratoelastoidosis

A marine bacterium, Micrococcus MCCB 104, antagonistic to vibrios in prawn larval rearing systems.

A marine bacterium, Micrococcus MCCB 104, isolated from hatchery water, demonstrated extracellular antagonistic properties against Vibrio alginolyticus, V. parahaemolyticus, V. vulnificus, V. fluviallis, V. nereis, V. proteolyticus, V. mediterranei, V cholerae and Aeromonas sp., bacteria associated with Macrobrachium rosenbergii larval rearing systems. The isolate inhibited the growth of V. alginolyticus during co-culture. The antagonistic component of the extracellular product was heat-stable and insensitive to proteases, lipase, catalase and alpha-amylase. Micrococcus MCCB 104 was demonstrated to be non-pathogenic to M. rosenbergii larvae.

Micrococcus-associated central venous catheter infection in patients with pulmonary arterial hypertension.

STUDY OBJECTIVES: To determine the incidence of catheter-related infection in patients with pulmonary arterial hypertension (PAH) receiving epoprostenol (EPO), and to note an etiologic role for Micrococcus spp, which is rarely reported as a pathogen in the medical literature. DESIGN: Observational study. SETTING: Two PAH specialty treatment centers, Harbor-UCLA Medical Center (Torrance, CA), and the College of Physicians and Surgeons, Columbia University (New York, NY). PATIENTS: A total of 192 patients with PAH receiving continuous therapy with IV EPO. INTERVENTIONS: From 1987 to 2000, 192 patients with PAH received infusions of EPO via central venous catheter. Catheter care included regular dressing changes with dry gauze using a sterile procedure, without the use of flushes. Patients were asked to report on known infections and treatments, and symptoms. All infections were verified by a telephone call to the patient, care provider, and microbiology laboratory whenever possible. MEASUREMENTS AND RESULTS: There were 335,285 catheter days (mean +/- SD, 1,325 +/- 974 catheter days). There were 88 clinical catheter infections with 51 blood culture-positive infections, necessitating catheter removal in 38 instances. The following pathogens were isolated: Staphylococcus aureus (25); Micrococcus spp (14); mixed flora (3); coagulase-negative Staphylococcus spp (2); Corynebacterium spp (2); Serratia marcessens (1); Enterobacter spp (1); Pseudomonas aeruginosa (1); enterococci (1); and unidentified Gram-positive cocci (1). The catheter infection rate was 0.26 per 1,000 catheter days. CONCLUSIONS: The use of long-term therapy with continuous EPO appears to be associated with a low incidence of catheter-related infections. Micrococcus spp were the second most common etiologic agent. Caregivers managing patients with PAH must be aware of the risk of catheter infection, as it may contribute to the morbidity and mortality associated with the use of EPO. When isolated, Micrococcus spp should not be viewed as a contaminant, but rather as a true pathogen that may require therapeutic intervention.

Micrococcus folliculitis in HIV-1 disease.

Organisms with little pathogenic potential in immunocompetent hosts may produce disease in HIV-1 + patients. We describe three HIV-1 + patients in late disease who presented with pruritic papules with central ulceration over the face and arms. In all the patients the eruptions had been present for months, and the patients did not develop sepsis. Biopsy specimens in all the patients showed large Gram-positive cocci, forming tetrads. Colony morphology, catalase positivity and coagulase negativity, and resistance to nitrofurantoin were used to separate micrococci from staphylococci. Micrococcus species are usually considered normal inhabitants of the skin; however, in patients with HIV-1 disease, Micrococcus species can produce localized cutaneous infections.

Gram-positive, catalase-positive cocci from dry cured Iberian ham and their enterotoxigenic potential.

Iberian ham is an uncooked, cured meat product ripened under natural uncontrolled conditions for 18 to 24 months. Gram-positive, catalase-positive cocci are the main microbial population in Iberian ham for most of the ripening time. Since some of these organisms are able to produce enterotoxins, adequate characterization and toxicological study are needed. For this, 1,327 gram-positive, catalase-positive cocci, isolated from Iberian hams at different stages and locations, were characterized by physiological and biochemical tests. Selected isolates were further characterized by guanine-cytosine (G+C) content and restriction enzyme analysis of genes coding for 16S rRNA. The toxigenic potential of these organisms was tested with specific DNA gene probes for staphylococcal enterotoxins A, B, C, and D and confirmed by semiquantitative sandwich enzyme immunoassay. The majority of the isolates were identified as Staphylococcus spp. and Micrococcus spp. Non-identified gram-positive, catalase-positive cocci which were moderately halophilic and showed a 42 to 52% G+C content were detected. A great variety of staphylococcal strains were found within the different species at any sampling time. Two strains of Staphylococcus xylosus, one Staphylococcus cohnii strain, and four of the non-identified organisms with 42 to 52% G+C contents hybridized with some of the DNA probes for C and D staphylococcal enterotoxin genes. S. xylosus hybridizing with C-enterotoxin probe reacted with both C and D enterotoxins in the immunological test. In addition, enterotoxin D was confirmed in the nonidentified strains. Some toxigenic organisms were isolated from the final product, posing a health hazard for the consumer.

[The probable utilization of the protective properties of the vector's saliva by the causative agents of specifically tick-borne infections]. / O veroiatnom ispol'zovanii zashchitnykh svoistv sliuny perenoschika vozbuditeliami spetsificheski kleshchevykh infektsii.

It is proved that in the tick fluid saliva and in the cement plug produced by Rhipicephalus appendiculatus there are bactericidal substances very similar in their activity to the egg lysozyme. The possible role in the transmission and conservation of the specific tick-borne, insensitive to the lysozyme pathogens such as rickettsiae, tick-borne encephalitides virus and borreliae (pathogen of Lyme disease) is discussed. It is supposed, that bactericidal substances in the cement plug protect accumulated in it the tick-borne pathogens (TBE virus, borreliae) from the compete and destructive influence of the vulgar, mainly coccal microflora and from the purulent inflammation, which hinders not only tick feeding but probably specific tick-borne pathogens spreading in the vertebrate host.

[Changes in the chromatin structure under the influence of intranuclear bacteria with antihistone activity]. / Izmeneniia v strukture khromatina pod vliianiem vnutriiadernykh bakterii s antigistonovoi aktivnost'iu.

Computed TV morphodensitometry was used to examine the integration of bacteria into the human nuclear genome. The bacterial strains with antihistone activity were shown to be incorporated into the structure of chromatin structure of an epithelial cell with its network organization impaired. The microscopic analysis of cultured Hep 2 cells by manual scanning indicated that genetically active bacteria were incorporated into the nucleus and nucleolus.

Intracranial suppuration caused by Micrococcus luteus.

Micrococcus spp. are commensal organisms colonizing the body surfaces of humans. In a few instances these organisms have been reported to colonize ventricular shunts. We report a patient, with no overt evidence of immunosuppression, in whom Micrococcus luteus was responsible for intracranial suppuration at multiple sites.

[Micrococcus luteus: a rare pathogen of valve prosthesis endocarditis]. / Micrococcus luteus: Ein seltener Erreger einer Klappenprothesenendokarditis.

A rare case of prosthetic valve endocarditis caused by Micrococcus luteus is described and compared with the few cases reported in the literature, as well as the clinical features, microbiological profile, therapy, and prognosis of common prosthetic valve endocarditis. Micrococcus luteus is a constituent of the normal human buccal bacterial flora which forms yellowish colonies and appears as a gram-positive coccus typically arranged in tetrades. Although of low virulence, the germ may become pathogenic in patients with impaired resistance, colonizing the surface of heart valves. In contrast to staphylococci (for which it may easily be mistaken) it is usually penicillin-sensitive. However, the most promising antibiotic regimen proposed for treatment of Micrococcus luteus seems to be a combination of vancomycin, amikacin, and rifampicin. If the infection leads to severe hemodynamic alterations, however, valve replacement may become necessary similar to the situation in prosthetic valve endocarditis caused by more aggressive and highly resistant bacteria.

Effects of Corynebacterium bovis infection on susceptibility to major mastitis pathogens.

Experimental challenge procedures were used to study infectivity and virulence of Corynebacterium bovis. Challenge procedures using Staphylococcus aureus (Newbould 305) and Streptococcus agalactiae (McDonald 44) were used to study effects of Corynebacterium bovis infections on superinfection with major pathogens. Rate of infection under experimental challenge conditions was significantly greater with Corynebacterium bovis than previously observed for Staphylococcus aureus or Streptococcus agalactiae. Principal location of Corynebacterium bovis colonization appeared to the teat canal region, although the organism was isolated from 75% of the teat cisterns by puncture technique. Quarters with Corynebacterium bovis infections were more resistant to infection by Staphylococcus aureus than bacteriologically negative quarters. Quarters infected with Corynebacterium bacterium bovis were approximately 8.5-fold more susceptible to Streptococcus agalactiae infection than negative quarters. Somatic cell counts were doubled in negative quarters that developed Corynebacterium bovis infections; the geometric mean was 2.4 X 10(5).