Diagnosis of mycobacterial infections based on acid-fast bacilli test and bacterial growth time and implications on treatment and disease outcome.

BACKGROUND: The establishment of therapeutic regimens for mycobacteriosis depends on the accurate identification of Mycobacterium species, and misdiagnosis can result in inappropriate treatment and increased mortality of patients. Differential diagnosis among Mycobacterium species has been made by conventional phenotypic and biochemical tests after a long culture period. Specialized molecular diagnostics of mycobacteria allows rapid detection and species identification; however, such tests are not available in public health programs. Our aim was to demonstrate the clinical implications of erroneous diagnosis by performing molecular genotyping of mycobacterial infections in patients that were diagnosed based on symptoms, culture and bacilloscopy. METHODS: Culture samples of mycobacterial infections from 55 patients clinically diagnosed as tuberculosis in 2013 and 2014, based on conventional methods, were identified by PCR -RFLP and results are discussed. RESULTS: We have confirmed 35 (63.6%) positive samples as M. tuberculosis, but 18 (32.7%) were identified as non-tuberculous mycobacteria (M. avium type 1, M. avium type 2, M. kansasii type 1 type 1, M. mucogenicum, M. chelonae, M. terrae type 3, and 1 unknown RFLP pattern) and two were negative. Regarding clinical diagnosis, 61.8% (34/55) was classified as pulmonary tuberculosis. It is important to emphasize that 36.4% (20/55) of samples were misdiagnosed by conventional methods, and 11 (61.1%) of the HIV positive patients (18/55) were NTM-coinfected. CONCLUSION: The identification of species in mycobacterial infections is essential for correct diagnosis and choice of treatment regimen, and misdiagnosis by conventional tools can lead to chronic disease, increased resistance and death.

[Prevalence of serotypes and antimicrobial resistance of invasive strains of Streptococcus pneumoniae]. / Prevalência de sorotipos e resistência antimicrobiana de cepas invasivas do Streptococcus pneumoniae.

OBJECTIVE: To determine the prevalence of serotypes and antimicrobial susceptibility of invasive strains of Streptococcus pneumoniae and to discuss the implications of these findings for vaccine formulation. METHODS: Strains of Streptococcus pneumoniae obtained from normally sterile fluids from patients admitted with invasive diseases were isolated and identified at the Hospital de Clínicas, Universidade Federal de Uberlândia, state of Minas Gerais, and forwarded to Instituto Adolfo Lutz, state of São Paulo, for further identification, serotyping and determination of antimicrobial susceptibility. RESULTS: From April 1999 to March 2003, 148 invasive strains of Streptococcus pneumoniae were obtained. The age of patients ranged from 1 day to 88.83 years (mean: 21.33+/-25.82 years; median: 4.42 years). Eighty-four (56.7%) patients were male. The most common diagnoses were pneumonia (91 cases; 61.4%), meningitis (32 cases; 21.6%) and occult bacteremia (15 cases; 10.1%). Strains were isolated mostly from blood (76 occasions; 51.3%), pleural fluid (39 occasions; 26.3%) and cerebrospinal fluid (30 occasions; 20.2%). There were 23 different serotypes, and the most common were 14, 3, 1, 5, 6A, 6B and 18C. Among 30 (20.2%) oxacillin-resistant strains, 23 (15.5%) were confirmed as resistant to penicillin (12.8% intermediate resistance and 2.7% full resistance). Oxacillin-resistant strains were restricted to serotypes 14, 23F, 19A and 6B. Resistance to penicillin varied with age, being more common in children under two years of age (p = 0.0008). We observed decreased sensibility to sulfamethoxazole-trimethoprim (92 isolates; 63.4%), to erythromycin (12 isolates; 8.3%), to clindamycin (12 isolates; 8.7%), to ofloxacin (one strain; 0.8%) and to cefotaxime (three strains; 2%; also resistant to penicillin). All isolates were susceptible to chloramphenicol, rifampin and vancomycin. CONCLUSIONS: The decreased susceptibility to penicillin, detected in 15.5% of the strains was predominant in children under two years of age. There were 23 different Streptococcus pneumoniae serotypes. The 23-valent polysaccharide vaccine covers 82.6% of the serotypes and 90.2% of the invasive strains isolated in this population. In addition, 46.7% of the serotypes and 63.6% of the strains isolated from children until five years of age are covered in the currently available 7-valent conjugated vaccine (PN CRM7).

Prevalência de sorotipos e resistência antimicrobiana de cepas invasivas do Streptococcus pneumoniae / Prevalence of serotypes and antimicrobial resistance of invasive strains of Streptococcus pneumoniae

OBJETIVO: Avaliar o perfil de sorotipos e a susceptibilidade aos antimicrobianos de cepas de Streptococcus pneumoniae obtidas em espécimes clínicos de pacientes com doença invasiva, bem como suas implicações na formulaçäo de vacinas pneumocócicas. MÉTODOS: Cepas de pneumococo isoladas no Laboratório de Análises Clínicas do Hospital de Clínicas da Universidade Federal de Uberlândia a partir de amostras clínicas de pacientes com doença invasiva foram identificadas e enviadas ao Instituto Adolfo Lutz em São Paulo para confirmaçäo da identificaçäo, sorotipagem e determinaçäo da susceptibilidade aos antimicrobianos. RESULTADOS: De abril de 1999 a março de 2003, foram isoladas 148 cepas invasivas de pneumococo, sendo 84 (56,7 por cento) provenientes de pacientes do sexo masculino. A idade variou de um dia a 88,83 anos, com média de 21,33+25,82 anos e mediana de 4,42 anos. Os diagnósticos clínicos mais comuns foram pneumonia (91 casos; 61,4 por cento), meningite (32 casos; 21,6 por cento) e bacteremia sem foco evidente (15 casos; 10,1 por cento). As principais fontes de recuperaçäo foram sangue (76 amostras; 51,3 por cento), líquido pleural (39; 26,3 por cento) e liquor (30; 20,2 por cento). No total, foram identificados 23 diferentes sorotipos entre 143 amostras testadas, sendo os mais comuns os seguintes: 14, 3, 1, 5, 6A, 6B e 18C. Dentre 30 (20,2 por cento) cepas oxacilina-resistentes, 23 (15,5 por cento) confirmaram a resistência à penicilina (12,8 por cento com nível intermediário e 2,7 por cento, com nível pleno), que esteve restrita aos sorotipos 14, 23F, 19A e 6B, predominando em indivíduos com até dois anos de idade (p = 0,0008). Foi detectada susceptibilidade diminuída ao cotrimoxazol (63,4 por cento), à eritromicina (8,3 por cento), à clindamicina (8,7 por cento) e à ofloxacina (0,8 por cento). A resistência à cefotaxima foi detectada em três das 30 cepas testadas (2 por cento das 148), todas elas com resistência confirmada à penicilina. Näo foi observada resistência a cloranfenicol, rifampicina ou vancomicina. CONCLUSÕES: A resistência à penicilina foi detectada em 15,5 por cento das cepas e predominou em crianças abaixo de dois anos de idade. Foram identificados 23 diferentes sorotipos de Streptococcus pneumoniae em pacientes internados com doença invasiva, e a maioria dos sorotipos (82,6 por cento) e das cepas (90,2 por cento) está incluída na vacina polissacarídica 23-valente