Estafilococos resistentes à oxacilina isolados em casos de mastite subclínica em ovinos / Oxacillin-resistant Staphylococci isolated from ovine subclinical mastitis

Bactérias do gênero Staphylococcus estão entre os principais agentes causadores da mastite ovina. Um dos maiores entraves ao tratamento dos animais doentes são cepas resistentes aos antimicrobianos empregados. A pesquisa do gene mecA nos estafilococos é um instrumento auxiliar para a determinação de aspectos epidemiológicos da doença. Este trabalho teve por objetivo investigar a resistência à oxacilina em estafilococos coagulase-negativos isolados no leite de ovelhas com mastite subclínica. Foram analisadas 448 amostras de leite de dois rebanhos. Os micro-organismos isolados foram submetidos previamente a testes de sensibilidade a antibióticos in vitro a partir da técnica de difusão em disco. Naqueles resistentes à oxacilina nestes testes efetuou-se a pesquisa do gene mecA, com a extração do DNA cromossômico por meio da técnica de extração fenol-clorofórmio. Os estafilococos coagulase-negativos apresentaram resistência à oxacilina e a presença do gene mecA foi detectada em quatro isolados, que também apresentaram características de multirresistência. Tais achados reforçam a importância deste grupo de micro-organismos na etiologia da mastite subclínica em ovinos e abre perspectivas para futuras pesquisas para a investigação da epidemiologia da doença.

OXACILLIN-RESISTANT STAPHYLOCOCCI ISOLATED FROM OVINE SUBCLINICAL MASTITIS. Staphylococcus bacteria are among the main agents of ovine mastitis. One of the greatest barriers to treatment of sick animals are strains resistant to antimicrobial agents. The research of the mecA gene in staphylococci is an auxiliary tool for the determination of epidemiological aspects of disease. The present study aimed to investigate oxacillin resistance in coagulase-negative staphylococci isolated in the milk from ewes with subclinical mastitis. A total of 448 samples from 2 flocks were analyzed. Colonies were previously submitted to testing for susceptibility to antibiotics in-vitro using the technique of disk diffusion. Using the oxacillin-resistant strains in these tests, the research of mecA gene was conducted with the extraction of chromosomal DNA by way of the technique of phenol-chloroform extraction. Coagulase-negative staphylococci were resistant to oxacillin, and the mecA gene was detected in 4 isolates, which also showed characteristics of multidrug resistance. These findings reinforce the importance of these microorganisms in the etiology of subclinical mastitis in ewes, and open perspectives for future research to investigate the epidemiology of this disease.

Estafilococos resistentes à oxacilina isolados em casos de mastite subclínica em ovinos / Oxacillin-resistant Staphylococci isolated from ovine subclinical mastitis

Bactérias do gênero Staphylococcus estão entre os principais agentes causadores da mastite ovina. Um dos maiores entraves ao tratamento dos animais doentes são cepas resistentes aos antimicrobianos empregados. A pesquisa do gene mecA nos estafilococos é um instrumento auxiliar para a determinação de aspectos epidemiológicos da doença. Este trabalho teve por objetivo investigar a resistência à oxacilina em estafilococos coagulase-negativos isolados no leite de ovelhas com mastite subclínica. Foram analisadas 448 amostras de leite de dois rebanhos. Os micro-organismos isolados foram submetidos previamente a testes de sensibilidade a antibióticos in vitro a partir da técnica de difusão em disco. Naqueles resistentes à oxacilina nestes testes efetuou-se a pesquisa do gene mecA, com a extração do DNA cromossômico por meio da técnica de extração fenol-clorofórmio. Os estafilococos coagulase-negativos apresentaram resistência à oxacilina e a presença do gene mecA foi detectada em quatro isolados, que também apresentaram características de multirresistência. Tais achados reforçam a importância deste grupo de micro-organismos na etiologia da mastite subclínica em ovinos e abre perspectivas para futuras pesquisas para a investigação da epidemiologia da doença. (AU)

OXACILLIN-RESISTANT STAPHYLOCOCCI ISOLATED FROM OVINE SUBCLINICAL MASTITIS. Staphylococcus bacteria are among the main agents of ovine mastitis. One of the greatest barriers to treatment of sick animals are strains resistant to antimicrobial agents. The research of the mecA gene in staphylococci is an auxiliary tool for the determination of epidemiological aspects of disease. The present study aimed to investigate oxacillin resistance in coagulase-negative staphylococci isolated in the milk from ewes with subclinical mastitis. A total of 448 samples from 2 flocks were analyzed. Colonies were previously submitted to testing for susceptibility to antibiotics in-vitro using the technique of disk diffusion. Using the oxacillin-resistant strains in these tests, the research of mecA gene was conducted with the extraction of chromosomal DNA by way of the technique of phenol-chloroform extraction. Coagulase-negative staphylococci were resistant to oxacillin, and the mecA gene was detected in 4 isolates, which also showed characteristics of multidrug resistance. These findings reinforce the importance of these microorganisms in the etiology of subclinical mastitis in ewes, and open perspectives for future research to investigate the epidemiology of this disease. (AU)

Estafilococos resistentes à oxacilina isolados em casos de mastite subclínica em ovinos

Staphylococcus bacteria are among the main agents of ovine mastitis. One of the greatest barriers to treatment of sick animals are strains resistant to antimicrobial agents. The research of the mecA gene in staphylococci is an auxiliary tool for the determination of epidemiological aspects of disease. The present study aimed to investigate oxacillin resistance in coagulase-negative staphylococci isolated in the milk from ewes with subclinical mastitis. A total of 448 samples from 2 flocks were analyzed. Colonies were previously submitted to testing for susceptibility to antibiotics in-vitro using the technique of disk diffusion. Using the oxacillin-resistant strains in these tests, the research of mecA gene was conducted with the extraction of chromosomal DNA by way of the technique of phenol-chloroform extraction. Coagulase-negative staphylococci were resistant to oxacillin, and the mecA gene was detected in 4 isolates, which also showed characteristics of multidrug resistance. These findings reinforce the importance of these microorganisms in the etiology of subclinical mastitis in ewes, and open perspectives for future research to investigate the epidemiology of this disease.

Bactérias do gênero Staphylococcus estão entre os principais agentes causadores da mastite ovina. Um dos maiores entraves ao tratamento dos animais doentes são cepas resistentes aos antimicrobianos empregados. A pesquisa do gene mecA nos estafilococos é um instrumento auxiliar para a determinação de aspectos epidemiológicos da doença. Este trabalho teve por objetivo investigar a resistência à oxacilina em estafilococos coagulase-negativos isolados no leite de ovelhas com mastite subclínica. Foram analisadas 448 amostras de leite de dois rebanhos. Os micro-organismos isolados foram submetidos previamente a testes de sensibilidade a antibióticos in vitro a partir da técnica de difusão em disco. Naqueles resistentes à oxacilina nestes testes efetuou-se a pesquisa do gene mecA, com a extração do DNA cromossômico por meio da técnica de extração fenol-clorofórmio. Os estafilococos coagulase-negativos apresentaram resistência à oxacilina e a presença do gene mecA foi detectada em quatro isolados, que também apresentaram características de multirresistência. Tais achados reforçam a importância deste grupo de micro-organismos na etiologia da mastite subclínica em ovinos e abre perspectivas para futuras pesquisas para a investigação da epidemiologia da doença.

Emergence of Klebsiella pneumoniae carrying the novel extended-spectrum beta-lactamase gene variants bla(SHV-40), bla(TEM-116) and the class 1 integron-associated bla(GES-7) in Brazil.

A clinical Klebsiella pneumoniae isolate carrying the extended-spectrum beta-lactamase gene variants bla(SHV-40), bla(TEM-116) and bla(GES-7) was recovered. Cefoxitin and ceftazidime activity was most affected by the presence of these genes and an additional resistance to trimethoprim-sulphamethoxazole was observed. The bla(GES-7) gene was found to be inserted into a class 1 integron. These results show the emergence of novel bla(TEM) and bla(SHV) genes in Brazil. Moreover, the presence of class 1 integrons suggests a great potential for dissemination of bla(GES) genes into diverse nosocomial pathogens. Indeed, the bla(GES-7) gene was originally discovered in Enterobacter cloacae in Greece and, to our knowledge, has not been reported elsewhere.

Carbapenem-resistant Acinetobacter baumannii outbreak at university hospital / Caracterização de cepas de Acinetobacter baumannii durante um surto de infecção hospitalar

Nineteen clonally related imipenem-resistant Acinetobacter baumannii isolates were recovered from eight intensive care unit patients. All isolates harboured blaOXA-51-like â-lactamase genes and showed the absence of 22 kDa fraction in outer membrane porin profile analysis. It suggests a combination of two mechanisms as responsible for carbapenemresistant phenotypes.

Foram isoladas 19 cepas monoclonais de 8 pacientes da unidade de terapia intensiva, resistentes aos carbapenêmicos. Todas as cepas apresentaram o gene blaOXA-51-like e por análise do perfil de proteínas de membrana notou-se ausência da fração de 22 kDa, sugerindo a combinação de dois mecanismos de resistência aos carbapenêmicos.

Detection of metallo-beta-lactamases-encoding genes in environmental isolates of Aeromonas hydrophila and Aeromonas jandaei.

AIMS: To determine the prevalence and expression of metallo-beta-lactamases (MBL)-encoding genes in Aeromonas species recovered from natural water reservoirs in southeastern Brazil. METHODS AND RESULTS: Eighty-seven Aeromonas isolates belonging to Aeromonas hydrophila (n = 41) and Aer. jandaei (n = 46) species were tested for MBL production by the combined disk test using imipenem and meropenem disks as substrates and EDTA or thioglycolic acid as inhibitors. The presence of MBL genes was investigated by PCR and sequencing using new consensus primer pairs designed in this study. The cphA gene was found in 97.6% and 100% of Aer. hydrophila and Aer. jandaei isolates, respectively, whereas the acquired MBL genes bla(IMP), bla(VIM) and bla(SPM-1) were not detected. On the other hand, production of MBL activity was detectable in 87.8% and 10.9% of the cphA-positive Aer. hydrophila and Aer. jandaei isolates respectively. CONCLUSIONS: Our results indicate that cphA seems to be intrinsic in the environmental isolates of Aer. hydrophila and Aer. jandaei in southeastern Brazil, although, based on the combined disk test, not all of them are apparently able to express the enzymatic activity. SIGNIFICANCE AND IMPACT OF THE STUDY: These data confirm the presence of MBL-producing Aeromonas species in natural water reservoirs. Risk of waterborne diseases owing to domestic and industrial uses of freshwater should be re-examined from the increase of bacterial resistance point of view.

Risk factors for colonisation of newborn infants during an outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in an intermediate-risk neonatal unit.

We describe a cross-sectional survey to identify risk factors for colonisation of neonates by extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae. This occurred following exposure to a colonised healthcare worker during an outbreak in an intermediate-risk neonatal unit. In total, 120 neonates admitted consecutively during a three-month period were screened for ESBL-producing K. pneumoniae by rectal swabbing and 27 were identified as colonised. Multivariate analysis showed colonisation to be independently associated with use of antibiotics and absence of breastfeeding. Previous use of antibiotics presented an odds ratio (OR) of 12.3 [95% confidence interval (CI): 3.66-41.2, P<0.001]. The most commonly used antibiotics were penicillin and amikacin. Breastfeeding was associated with reduced risk for colonisation (OR: 0.22; 95% CI: 0.05-0.99; P=0.049). Nine isolates recovered during the first stage of the outbreak and 27 isolates from surveillance cultures were typed thereafter by pulsed-field gel electrophoresis, revealing six different profiles (A-F). Clones A, C, and E were implicated in the first stage of the outbreak, whereas among the 27 strains recovered from surveillance cultures, all six clones were identified. Clone A was also found on the hand of a nursing auxiliary with onychomycosis. We concluded that prior antimicrobial use predisposed to colonisation. The possible role of breastfeeding as a protective factor needs to be further elucidated. Detection of different genotypes of ESBL-producing K. pneumoniae suggests that dissemination of mobile genetic elements bearing the ESBL gene may have been superimposed on the simple dissemination of a clone during the outbreak.

Carbapenem-resistant Acinetobacter baumannii outbreak at university hospital.

Nineteen clonally related imipenem-resistant Acinetobacter baumannii isolates were recovered from eight intensive care unit patients. All isolates harboured bla OXA-51-like ß-lactamase genes and showed the absence of 22 kDa fraction in outer membrane porin profile analysis. It suggests a combination of two mechanisms as responsible for carbapenem-resistant phenotypes.

Carbapenem-resistant Acinetobacter baumannii outbreak at university hospital

Nineteen clonally related imipenem-resistant Acinetobacter baumannii isolates were recovered from eight intensive care unit patients. All isolates harboured blaOXA-51-like -lactamase genes and showed the absence of 22 kDa fraction in outer membrane porin profile analysis. It suggests a combination of two mechanisms as responsible for carbapenemresistant phenotypes.

Foram isoladas 19 cepas monoclonais de 8 pacientes da unidade de terapia intensiva, resistentes aos carbapenêmicos. Todas as cepas apresentaram o gene blaOXA-51-like e por análise do perfil de proteínas de membrana notou-se ausência da fração de 22 kDa, sugerindo a combinação de dois mecanismos de resistência aos carbapenêmicos.

pncA mutations in pyrazinamide-resistant Mycobacterium tuberculosis clinical isolates from the southeast region of Brazil.

OBJECTIVES: To investigate the presence of mutations in the pncA gene in 31 pyrazinamide-resistant Mycobacterium tuberculosis and 5 susceptible strains. MICs and pyrazinamidase (PZase) activity were also determined. METHODS: All 36 M. tuberculosis clinical isolates were genotyped by mycobacterial interspersed repetitive units (MIRUs) and most were also typed by spoligotyping. The MIC value necessary to inhibit 99% of the resistant mycobacterial isolates was determined by microplate Alamar Blue assay (MABA) and by Löwenstein-Jensen assay (LJA). The PZase activity was measured by pyrazinamide deamination to pyrazinoic acid and ammonia, and the entire pncA sequence including the 410 bp upstream from the start codon was determined by DNA sequencing of purified PCR products. RESULTS: Of the 31 isolates resistant to pyrazinamide, 26 (83.9%) showed at least one mutation in the pncA gene or in its putative regulatory region. Among the 22 different mutations detected in the pncA gene and in its regulatory region, 9 (40.9%) mutations (consisting of six substitutions, two insertions and one deletion) have not been described in previous studies. Three pyrazinamide-resistant isolates, confirmed by MIC varying from 800 to 1600 mg/L, carried the wild-type pncA sequence and retained PZase activity. CONCLUSIONS: These results contribute to the knowledge of the molecular mechanism of pyrazinamide resistance in Brazil and also expand the profile of pncA mutations worldwide. The MABA was successfully used to determine the MICs of pyrazinamide.

Molecular characterization of van genes found in vancomycin-resistant Enterococcus spp. isolated from the Hospital das Clínicas, FMUSP, São Paulo, Brazil.

Vancomycin-resistant enterococci strains (VRE) is an important pathogen related with hospital infections in many countries, presenting limited or no therapeutic options for treating serious infections. VRE has presented some different genotypes been VanA and VanB considered to be the most important in hospital environments. In the present study the authors investigated the prevalence of van genes (A, B an C) among clinical isolates of VRE in a five month period at a large tertiary hospital in Sao Paulo, Brazil. The results showed the presence of vanA, but not vanB or vanC in all 43 strains of E. faecalis and five E. faecium studied. The results bring an important issue, due to the possibility of resistance spread of vanA genes, to be monitored and solved by the hospital infection control team and the microbiology and molecular biology laboratories at tertiary Hospitals.

Molecular techniques for MRSA typing: current issues and perspectives.

Staphylococcus aureus has long been recognised as an important pathogen in human disease. Serious staphylococcal infections can frequently occur in inpatients and may lead to dire consequences, especially for therapy with antimicrobial agents. The increase in the frequency of Methicillin-Resistant Staphylococcus aureus (MRSA) as the causal agent of nosocomial infection and the possibility of emergence of resistance to vancomycin demands a quick and trustworthy characterization of isolates and identification of clonal spread within hospitals. Enough information must be generated to permit the implementation of appropriate measures for control of infection, so that outbreaks can be contained. Molecular typing techniques reviewed in this manuscript include: plasmid profile analysis, analysis of chromosomal DNA after enzymatic restriction, Southern blotting, pulsed field gel electrophoresis (PFGE), techniques involving polymerase chain reaction and multilocus sequence typing (MLST). Repetitive DNA Sequence PCR (rep-PCR) may be used for screening due to its practicality, low cost and reproducibility. Because of its high discriminatory power Pulsed-Field Gel Electrophoresis (PFGE) still remains the gold standard for MRSA typing. New techniques with higher reproducibility and discriminatory power, such as Multi-Locus Sequence Typing (MLST), are appearing. These are mostly useful for global epidemiology studies. Molecular typing techniques are invaluable tools for the assessment of putative MRSA outbreaks and so should be extensively used for this purpose.

Molecular characterization of van genes found in vancomycin-resistant Enterococcus spp. isolated from Hospital das Clínicas, FMUSP, Säo Paulo, Brazil

Vancomycin-resistant enterococci strains (VRE) is an important pathogen related with hospital infections in many countries, presenting limited or no therapeutic options for treating serious infections. VRE has presented some different genotypes been VanA and VanB considered to be the most important in hospital environments. In the present study the authors investigated the prevalence of van genes (A, B an C) among clinical isolates of VRE in a five month period at a large tertiary hospital in Sao Paulo, Brazil. The results showed the presence of vanA, but not vanB or vanC in all 43 strains of E. faecalis and five E. faecium studied. The results bring an important issue, due to the possibility of resistance spread of vanA genes, to be monitored and solved by the hospital infection control team and the microbiology and molecular biology laboratories at tertiary Hospitals

Molecular techniques for MRSA typing: current issues and perspectives

Staphylococcus aureus has long been recognised as an important pathogen in human disease. Serious staphylococcal infections can frequently occur in inpatients and may lead to dire consequences, especially as to therapy with antimicrobial agents. The increase in the frequency of Methicillin-Resistant Staphylococcus aureus (MRSA) as the causal agent of nosocomial infection and the possibility of emergence of resistance to vancomycin demands a quick and trustworthy characterization of isolates and identification of clonal spread within hospitals. Enough information must be generated to permit the implementation of appropriate measures for control of infection, so that outbreaks can be contained. Molecular typing techniques reviewed in this manuscript include: plasmid profile analysis, analysis of chromosomal DNA after enzymatic restriction, Southern blotting, pulsed field gel electrophoresis (PFGE), techniques involving polymerase chain reaction and multilocus sequence typing (MLST). Repetitive DNA Sequence PCR (rep-PCR) may be used for screening due to its practicality, low cost and reproducibility. Because of its high discriminatory power Pulsed-Field Gel Electrophoresis (PFGE) still remains the gold standard for MRSA typing. New techniques with higher reproducibility and discriminatory power, such as Multi-Locus Sequence Typing (MLST), are appearing. These are mostly useful for global epidemiology studies. Molecular typing techniques are invaluable tools for the assessment of putative MRSA outbreaks and so should be extensively used for this purpose

Characterization of the Brazilian endemic clone of methicillin-resistant Staphylococcus aureus (MRSA) from hospitals throughout Brazil.

The objective of this study was to characterize patterns of the Brazilian endemic clone of methicillin-resistant Staphylococcus aureus (MRSA) from hospitals throughout Brazil. We studied 83 MRSA strains isolated from patients hospitalized in 27 public and private hospitals in 19 cities located in 14 Brazilian states from September, 1995, to June, 1997. The MRSA strains were typed using antibiograms, bacteriophage typing and pulsed field gel electrophoresis (PFGE). The analysis of genomic DNA by PFGE showed that 65 isolates presented the same PFGE pattern. This pattern was present in all of the hospitals studied indicating the presence of an endemic MRSA clone widely disseminated throughout Brazilian hospitals (BEC). All isolates belonging to the BEC proved to be resistant to ciprofloxacin, erythromycin, lincomycin, trimethoprim-sulphamethoxazole, and tetracycline. Variable susceptibility to these drugs was found only in isolates belonging to clones other than the BEC. The results show that, among MRSA, the BEC is common in Brazil. The best method for mapping changes in the frequency of this clone among MRSA is pulsed field gel electrophoresis. Use of molecular mapping is an important tool for monitoring the spread of potentially dangerous microbes.

Experimental infection and horizontal transmission of Bartonella henselae in domestic cats.

In order to study B. henselae transmission among cats, five young cats were kept in confinement for two years, one of them being inoculated by SC route with B. henselae (10(5) UFC). Only occasional contact among cats occurred but the presence of fleas was observed in all animals throughout the period. Blood culture for isolation of bacteria, PCR-HSP and FTSZ (gender specific), and BH-PCR (species-specific), as well as indirect immunofluorescence method for anti-B. henselae antibodies were performed to confirm the infection of the inoculated cat as well as the other naive cats. Considering the inoculated animal, B. henselae was first isolated by blood culture two months after inoculation, bacteremia last for four months, the specific antibodies being detected by IFI during the entire period. All contacting animals presented with bacteremia 6 months after experimental inoculation but IFI did not detect seroconversion in these animals. All the isolates from these cats were characterized as Bartonella (HSP and FTSZ-PCR), henselae (BH-PCR). However, DNA of B. henselae could not be amplified directly from peripheral blood by the PCR protocols used. Isolation of bacteria by blood culture was the most efficient method to diagnose infection compared to PCR or IFI. The role of fleas in the epidemiology of B. henselae infection in cats is discussed.

Isolation in Brazil of nosocomial Staphylococcus aureus with reduced susceptibility to vancomycin.

OBJECTIVE: To evaluate the possible presence of vancomycin-resistant Staphylococcus aureus (VRSA) in a Brazilian hospital. DESIGN: Epidemiological and laboratory investigation of nosocomial VRSA. METHODS: 140 methicillin-resistant S aureus strains isolated between November 1998 and October 1999 were screened for susceptibility to vancomycin. The screening was carried out by using brain-heart infusion agar (BHIA) supplemented with 4, 6, and 8 microg/mL of vancomycin. The minimum inhibitory concentration (MIC) determination was carried out as standardized by the National Committee for Clinical Laboratory Standards using the broth macrodilution, agar-plate dilution, and E-test methods. PATIENTS: Hospitalized patients exposed to vancomycin. RESULTS: 5 of the 140 isolates had a vancomycin MIC of 8 microg/mL by broth macrodilution, agar plate dilution, and E-test methods. Four VRSA strains were isolated from patients in a burn unit who had been treated with vancomycin for more than 30 days, and one from an orthopedic unit patient who had received vancomycin treatment for 7 days. Pulsed-field gel electrophoresis characterized four of the VRSA strains as belonging to the Brazilian endemic clone. All five strains were negative for vanA, vanB, and vanC genes by polymerase chain reaction. Transmission electron microscopy of the five strains revealed significantly thickened cell walls. One patient died due to infection caused by the VRSA strain. CONCLUSIONS: This is the first report of isolation of VRSA in Brazil and the first report of isolation of multiple VRSA strains from one facility over a relatively short period of time. This alerts us to the possibility that VRSA may be capable of nosocomial transfer if adequate hospital infection control measures are not taken.

Evaluation of Henes-PCR assay for Mycobacterium detection in different clinical specimens from patients with or without tuberculosis-associated HIV infection.

The need for early diagnosis of tuberculosis, particularly in HIV-infected patients, requires the development of diagnosis methods that have a high sensitivity and specificity, as does the nucleic acid-based technology. With the purpose of improving the detection of mycobacterium in different clinical samples, we proposed and evaluated an assay based on nucleic acid-amplification: heminested-PCR (Henes-PCR). The procedure was designed to identify Mycobacterium spp., M. tuberculosis complex (MTC), and M. avium complex (MAC), although it has the potential to include more primers for the identification of other species. Analytical and clinical evaluation of Henes-PCR was performed by analysis of reference strains and 356 clinical specimens from 246 patients with pulmonary and meningitis tuberculosis and unrelated infections, including 142 HIV-infected individuals. Ninety-three percent (199) positive and 100% (143) negative results were obtained in specimens from patients with tuberculosis and non-tuberculosis infection, respectively. The overall sensitivity of Henes-PCR was 93.4%, specificity was 100%, positive and negative predictive values were 100 and 91.1%, respectively. Sensitivity and negative predictive value of Henes-PCR were significantly higher than culture procedure for microscopy-negative specimens. Even though frequency of HIV infection was higher in patients with tuberculosis, diagnostic parameters of Henes-PCR were similar between HIV-positive and HIV-negative patients. MTB was identified in 194 (98%) specimens while MAC was detected in 5 (2%) specimens. These findings suggest that Henes-PCR is a useful test for rapid detection of mycobacterium in clinically suspected cases of tuberculosis with smear-negative results.

Microbiologic aerobic studies on normal male urethra.

OBJECTIVES: To carefully collect samples from the external urethral orifice, navicular fossa, and penile urethra and perform a semiquantitative evaluation and identification of gram-positive and gram-negative bacteria present in the normal male urethra. METHODS: Thirty uncircumcised male patients 18 to 40 years old without any inflammatory and/or infectious urethral processes were enrolled in this study. Samples were collected from the external urethral orifice, navicular fossa, and penile urethra with sterile alginate swabs that were immediately transferred to tubes containing buffered phosphate solution. Inoculation was done by spreading 0.01 mL of the buffered solutions on sheep blood agar plates and MacConkey agar plates; the plates were then incubated at 36.5 degrees C for 24 hours. After this period, the quantification and identification of each type of colony was performed. RESULTS: Among the 30 patients studied, 12 (40%) had bacteria isolated from the three segments, 10 (33.3%) had bacterial colonization in two segments, and 8 (26.7%) had colonization in only one segment (external urethral orifice). Staphylococcus coagulase-negative species, group viridans alpha-hemolytic streptococci, Corynebacterium species, and Enterococcus species were the bacteria more frequently isolated from these three segments. CONCLUSIONS: From the findings in this study, it was clear that the bacterial urethral flora was abundant, not evenly distributed, concentrated in the external urethral orifice and navicular fossa, and basically consisted of gram-positive aerobic bacteria.