[Newborn intestinal colonization by multidrug resistant enterobacteria in a neonatal unit] / Colonização intestinal de recém-natos por enterobactérias multirresistentes a antimicrobianos em unidade neonatal.

OBJECTIVE: To evaluate the occurrence of intestinal colonization in newborns by multidrug-resistant enterobacteria strains (MDRES) during hospital stay after birth. We used selective media in an attempt to determine the relationship between isolation of these strains and some of the presumed colonization risk factors. METHOD: A sequencial inclusion study of 30 newborns was carried out in the neonatal unit of the HUPE, State University Hospital, a general 600-bed tertiary care hospital. We obtained clinical and epidemiological information from medical records and collected a fecal sample from each newborn, which was plated in gentamicin (8mg/ml) medium and potassium tellurite (25mg/ml) medium. The isolated strains were biochemically identified and also submitted to tests of antimicrobial susceptibility. Nine MDRES were submitted to an assay for plasmid conjugational transfer. RESULTS: We isolated 56 distinct MDRES from 14 among 30 newborns (46.7%). Klebsiella pneumoniae was the most common bacterial species (38/56 (68%). We found statistical association between individual MDRES isolation and presence of 3 or 4 of the following colonization risk factors considered: antimicrobial use, low weight (<2.500g), more than 6 days of hospitalization and artificial milk feeding (p< 0.02). We could detect plasmid resistance transfer by bacterial conjugation for 8 among 9 MDRES. CONCLUSION: The seletive cultura media were useful to detect the high frequence of newborns colonized by MDRES in association with well established infection risk factors. We emphasize the importance of reinforcing control rules aiming at preventing intestinal colonization viewed as a risk of nosocomial infection.

Use of a selective medium with potassium tellurite to follow intestinal colonization of hospitalized patients by drug-resistant Enterobacteriaceae.

Nosocomial infections are a relevant factor in complicating the recovery of patients interned for even minor causes. In a attempt to determine their origin it is crucial to consider that their origin is of an endogenous nature. Looking for an accessible expression of intestinal colonization we analyzed fecal samples from 3 separate groups of hospital patients collected after different lengths of time. For practical reasons one group was studied prospectively and two other groups (patients hospitalized for up to 7 days and patients hospitalized for more than 7 days) were compared to one another. We looked for the emergence of tellurite resistance among Enterobacteriaceae using a selective medium, MacConkey potassium tellurite (MCPT). The frequency of prospectively studied patients with tellurite resistant strains was significantly greater after 7 days of hospitalization. For the two other groups, patients with more than 7 days of hospitalization showed a significant increase of bacterial species and of strains with new antimicrobial resistance markers. High molecular weight plasmids were detected in some of these strains. These data show that the MCPT medium is a useful tool for the investigation of bowel colonization in hospitalized patients by drug-resistant Enterobacteriaceae.

Isolation of Pseudomonas cepacia in cystic fibrosis patient.

Pulmonary infection on cystic fibrosis (CF) patients are associated with a limited qualitative number of microorganisms. During the colonization process, Staphylococcus aureus usually precedes Pseudomonas aeruginosa. This latter is at first non-mucoid, being replaced or associated to a mucoid morphotype which is rare in other diseases. In 1980, Pseudomonas cepacia appeared as an important agent in CF pulmonary infections with a mean frequency of about 6.1% isolations in different parts of the world. The primus colonization mainly occurs in the presence of pre-existent tissue lesions and the clinical progress of the disease is variable. In some patients it can be fulminant; in others it can cause a gradual and slow decrease in their pulmonary functions. The concern with this germ isolation is justified by its antibiotic multiple resistance and the possibility of direct transmission from a colonized patient to a non-colonized one. We reported the first case of P. cepacia infection in a CF patient in our area. The microbiological attendance to this patient had been made from 1986 to 1991 and the first positive culture appeared in 1988. The sensitivity profile showed that the primus colonization strain was sensitive to 9 of 17 tested antibiotics, however in the last culture the strain was resistant to all antibiotics. These data corroborate the need for monitoring the bacterial flora on CF patients respiratory system.

[In vitro susceptibility to a new antimicrobial agent (imipenem) of pathogens isolated from inpatients at various centers]. / Estudo da suscetibilidade "in vitro" a um novo antimicrobiano (imipenem) de patógenos isolados de pacientes hospitalares em vários centros.

Imipenem is a beta lactam antibiotic, a highly potent new carbapenem with broad antibacterial spectrum. To test the "in vitro" efficacy of this antimicrobial agent in pathogens more frequent in several Medical Centers in Brazil, susceptibility testing with 10 mcg imipenem disks and, or corresponding MIC were carried out with 1231 recent isolates of 41 different bacterial species, obtained mainly from hospitalized patients in 5 different medical centers of the cities of S. Paulo, Rio de Janeiro and Salvador. Our preliminary results with this antibiotic, in final phases of clinical and laboratorial experimentation in this country, are very promissing with, 96.79% of susceptibility of test isolates to 10 mcg imipenem disks and corresponding MIC correlation of up to 4 micrograms/ml. (92.31%). Of the 9 bacterial species more frequently isolated totaling 1108 (82%) of the 1230 test isolates, disk susceptibility was 99% (E. coli), 93% (Pseudomonas aeruginosas), 87% (Staphylococcus aureus), 100% (Klebsiella pneumoniae), 98% (Klebsiella sp), 97% (Proteus mirabiles), 94% (Enterobacter sp), 100% (Streptococcus faecalis) with good MIC correlation (up to 8 mcg/ml) and 100% for the anaerobic species Bacteroides sp (MIC up to 4 micrograms/ml). "In vitro" efficacy to hospital pathogens with high frequency of resistance to most antibiotics as Pseudomonas aeruginosa and to anaerobes notably Bacteroides sp is emphasized.

An endocytic process in HEp-2 cells induced by enteropathogenic Escherichia coli.

Infection of HEp-2 cells by enteropathogenic Escherichia coli (EPEC) was examined by transmission and scanning electronmicroscopy. EPEC strains of serogroups O111:K58 and O55:K59 recently isolated from human patients did not exhibit enterotoxic activity, as judged by the Vero-cell and suckling-mouse assays, or invasive ability as judged by the Sereny test. These strains attached to and penetrated HEp-2 cells. Transmission electronmicroscopy showed bacteria in close contact with cell membranes 15 min after infection; later, intense swelling and budding of membranes and penetration of EPEC into the cell cytoplasm occurred. Intracellular bacteria were enclosed in membrane-bound vacuoles in the cell cytoplasm underlying localised adherence sites observed by light microscopy. Scanning electronmicroscopy showed morphologically altered membranes only at the sites of bacterial attachment. Bacteria inactivated by ultraviolet light were not internalised and cytochalasin B (greater than or equal to 10 mg/L) markedly inhibited uptake. These observations suggest that penetration of EPEC into HEp-2 cells occurs by an endocytic process in metabolically active bacteria.

[Cytotoxic and hemolytic activities in uropathogenic Escherichia coli]. / Atividades citotóxica e hemolítica em Escherichia coli uropatogênicas.

Fifty nine Escherichia coli strains obtained from patients with upper or lower urinary tract infections (UTI) and 30 E. coli strains isolated from stools of healthy individuals were tested for hemolytic and cytotoxic activities. Forty four percent of uropathogenic E. coli (UPEC) and 3.3% of fecal E. coli were hemolytic. Among the hemolytic UPEC, 92% produced alpha-hemolysin. A cytotoxic activity was detected in culture filtrates of 71% of UPEC strains and 30% of fecal E. coli. No relationship was found between cytotoxic and hemolytic activities or between cytotoxic titers and UPEC origin (upper or lower UTI). E. coli cytotoxin has a cytocidal activity against some epithelioid cultured cell lines (Vero, HeLa and Hep-2) but was almost inactive for avian-fibroblast cells. Cytotoxin-affected cells appeared rounded, refractile and detached from the surface of the vessel. Some characteristics exhibited by the cytotoxin as the morphological response induced on cells, the increasing of cytopathic effect with time, its irreversible cytocidal activity and its heat-lability resemble the properties described for E. coli Verotoxin (VT). Adherence to uroepithelial cells is recognized as a virulence factor for UPEC. It is suggested that cell damage by cytotoxic and adhering UPEC might contribute to E. coli virulence to urinary tract.

Evaluation of humoral and cellular immunity in patients with urinary tract infections.

The cellular and humoral immunity of 15 patients with recurrent urinary tract infections was assessed during infection. We determined the reactivity of peripheral blood lymphocytes to microbial antigens (PPD, streptolysin O, tetanus toxoid, Salmonella typhi and Escherichia coli), to allogenic cells, and to mitogens (phytohemagglutinin, concanavalin A, pokeweed mitogen and jacalin). T and B cells were counted by the rosette technique. We also evaluated serum immunoglobulins and C3 and C4 levels by radial immunoprecipitation and specific antibodies for the etiological agent by direct agglutination, hemagglutination and indirect immunofluorescence. Urinary antibodies were assessed by the antibody-coated bacteria test (ACB). Some patients were retested for cellular immune function after cure. No significant alteration of immunoglobulin levels was detected, except for two patients who showed elevated IgM levels. C3 and C4 were elevated in one and in five cases, respectively. Specific serum antibodies for the etiological agent were present in all patients but their levels did not differ from those of normal controls. In only five patients were urinary antibodies detected by the ACB test. Patients' peripheral blood lymphocyte reactivity was depressed during infection for most of the microbial antigens and mitogens tested and returned to normal levels after cure. T and B cell numbers were within the normal range.

[Biotyping and resistotyping for epidemiological tracing of the fecal origin of Klebsiella pneumoniae in urinary infections]. / Biotipagem e resistotipagem para o traçado epidemiológico da origem fecal de Klebsiella pneumoniae em infecções urinárias.

Twenty-four (82.7%) out of 29 patients suffering from hospital acquired urinary infections by Klebsiella pneumoniae had the same species in their faeces. Biotyping of 24 urinary and 219 fecal strains of K. pneumoniae resulted in 50 different biotypes - an average of four biotypes per fecal sample. Ten patients (34.4%) had the same biotype in urine and faeces without any correlation with previous vesical catheterization (p greater than 0.05). Using resistotyping to four chemical compounds selected among 34 tested substances (brilliant green, malachite green, potassium tellurite and mercuric chloride) 16 different resistotypes were found. Fourteen patients (58.3%) presented the same resistotype in urine and faeces but only in five patients was there correlation with simultaneous biotyping identity. Simultaneous occurrence of identical biotypes or resistotypes in faeces and urine occurred in only 54.2% of cases. However, there was a significant association between resistance ot mercuric and tellurite ions in fecal and urinary strains isolated from the same patient (p less than 0.001).

Fenomeno de Dienes em Proteus: ausencia de correlacao com a estrutura antigenica e a producao de metabolitos difusiveis. / Dienes phenomenon in Proteus: lack of correlation to antigenic structure and to production of diffusible metabolites

O fenomeno de Dienes consiste na formacao de linha de demarcacao no local de encontro do crescimento invasivo de duas amostras de estirpes diferentes de Proteus, quando se defrontam na superficie de meio solido. O estudo de amostras de P. mirabilis e de P. vulgaris nao revelou correlacao entre estrutura antigenica e a antibiose bacteriana evidenciada pelo teste de Dienes. Tambem nao foi possivel detectar substancias toxicas as quais se pudesse atribuir a inibicao do espraiamento,no confronto de cepas incompativeis

Mannose-resistant hemaglutinins and pili in Escherichia coli associated to urinary tract infections.

Em Escherichia coli, isoladas de infeccoes urinarias, foram detectadas diversas hemaglutininas (pili) manose-resistentes. A mais frequente delas associa-se ao sorogrupo 06, aglutinando apenas hemacias de carneiro

Sorotipos de Shigella em gastroenterites no Rio de Janeiro. / Serotypes of Shigella isolated from gastroenteritis in Rio de Janeiro

Comparacao do comortamento bioquimico e sorologico de 175 amostras de Shigella isoladas de corprocultura de pacientes com gastroenterite aguda de intensidade variavel, ou historia de diarreia cronica, na cidade do Rio de Janeiro, em dois periodos 1960 a 1969 (89 amostras) e 1970 a 1978 (86 amostras). Foi evidenciada a prevalencia do subgrupo B (64,00%) seguido do subgrupo D (26,30%) e a baixa incidencia dos subgrupos C (5,70%) e A (4,00%). A sorotipagem revelou a predominancia dos sorotipos B2 (26,80%) e D (26,30%), seguidos de B3 (16,00%) e B1 (12,00%).Nao foram observadas alteracoes marcantes na distribuicao dos sorotipos de maior frequencia nos dois periodos de isolamento

Comparacao de meios de cultura para o isolamento do Corynebacterium minutissimum dos espacos interdigitais dos pes. / Comparison of culture media in the isolation of Corynebacterium minutissimum from interdigital spaces of toes

A comparacao de meios para isolamento do agente etiologico do eritrasma demonstrou que o meio de Mueller-Hinton nao e adequado para pesquisa da fluorescencia sob luz ultravioleta no isolamento primario, que o meio de Pai nao e satisfatorio para o isolamento com leitura realizada apos 18 horas de incubacao e que o maior numero de isolamentos pode ser feito em agar chocolate telurico. O estudo de amostras isolaladas de 24 individuos mostrou que "difteroides" inicialmente apresentado fluorescia rosea, passaram a fluorescencia vermelho-coral quando retestadas. Em dois casos de eritrasma foram isolados somente "difteroides" com fluorescencia alaranjada e observamos tambem que ate tres tipos coloniais diferentes de "difteroides" fluorescentes sao isolados a partir do mesmo paciente