Prevalent Etiological Agent Research Articles

Manejo da gangrena de Fournier: experiência de um hospital universitário de Curitiba

To analyze the results obtained in the Department of General Surgery, Cajuru University Hospital-PUCPR, with the treatment of Fournier's gangrene. We reviewed the charts of 40 patients diagnosed with Fournier's gangrene admitted to the Cajuru University Hospital from November 1999 to April 2006, analyzing gender, age, predisposing factors, etiology, lesion location, laboratory tests, surgical procedures, antibiotic use and hyperbaric oxygen therapy. The most common etiology was the anorectal origin. The most prevalent etiological agent was E. coli. The predominant predisposing factor was diabetes mellitus. The majority of patients were male. The location and extent of injury was usually in the perineum. All underwent surgical debridement, 17 with associated colostomy and two with combined cystostomy. All patients received antibiotics, the most used being metronidazole and gentamicin. Twenty-six patients underwent hyperbaric therapy. The overall mortality was 20%. Fournier's syndrome, despite all the advances in treatment today, continues to show high mortality rates. Early recognition of infection associated with invasive and aggressive treatment are essential for attempting to reduce these prognostic indices.

Murine model of chronic L. (Viannia) panamensis infection: Role of IL‐13 in disease

Leishmania (Viannia) organisms are the most prevalent etiologic agents of human cutaneous leishmaniasis in the Americas. Nevertheless, our knowledge of the immunological mechanisms exploited by L. (Viannia) organisms remains limited and the mechanisms underlying disease are not well understood. Here, we report the development of a BALB/c mouse model of L. (V.) panamensis infection that is able to reproduce chronic disease, with persistent infection and clinically evident lesions for over 1 year. The immune response of the mouse resembles that found for L. (V.) panamensis-infected patients with chronic and recurrent lesions, presenting a mixed Th1/Th2 response with the presence of TNF-α, IFN-γ, IL-10 and IL-13. Using immunodeficient mice, the critical role for IL-13 and/or IL-4Rα in determining susceptibility to chronic infection was evident. With the induction of healing in the immunodeficient mice, increases in IFN-γ and IL-17 were found, concomitant with parasite control and elimination. Specifically, increases in CD4(+) (but not CD8(+)) T cells producing IFN-γ were observed. These results suggest that IL-13 represents an important target for disease control of L. (V.) panamensis infection. This murine model should be useful to further understand the pathology associated with chronic disease and to develop methods for the treatment and prevention of leishmaniasis caused by L. (Viannia) parasites.

Prevalence and etiologic agents of female reproductive tract infection among in-patients and out-patients of a tertiary hospital in Benin city, Nigeria

Background:Reproductive tract infections are public health problems in women of reproductive age and can result in serious consequences if not treated.Aims:To determine the prevalence and causes of reproductive tract infections among in-patients and out-patients attending a tertiary health institution in Benin City. The antimicrobial susceptibility profiles of bacterial agents will also be determined.Patients and Methods:High vaginal swabs or endocervical swabs and blood were collected from 957 patients consisting of 755 out-patients and 202 in-patients. The swabs were processed and microbial isolates identified using standard technique. Disc susceptibility tests were also performed on microbial isolates. The blood samples were used for serological diagnosis of syphilis.Results:There was no significant difference in the prevalence of female reproductive tract infections between in-patients (52.48%) and out-patients (47.02%), although in-patients showed a significantly higher risk of developing mixed infections (in-patients vs. out-patients; 34.91% vs. 22.25%, OR = 1.873 95% CI = 1.169, 3.001; P = 0.01). Candida albicans was the most prevalent etiologic agent among out-patients studied while Staphylococcus aureus was the most prevalent etiologic agent among in-patients. Trichomonas vaginalis was observed only among out-patients. Ceftriaxone, ciprofloxacin and ofloxacin were the most active antibacterial agents. Syphilis was not detected in any patient.Conclusion:An overall prevalence of 48.17% of female reproductive tract infection was observed among the study population. Although there was no significant difference between in-patients and out-patients, in-patients appeared to have 1-3-fold increase risk of developing mixed infections. The most prevalent etiologic agent differs between in-patients and out-patients. Despite the high activity of ceftriaxone, ciprofloxacin and ofloxacin against bacterial isolates from both in-patients and out-patients, prudent use of antibacterial agents is advocated.

Identification of a Modular Pathogenicity Island That Is Widespread among Urease-Producing Uropathogens and Shares Features with a Diverse Group of Mobile Elements

Pathogenicity islands (PAIs) are a specific group of genomic islands that contribute to genomic variability and virulence of bacterial pathogens. Using a strain-specific comparative genomic hybridization array, we report the identification of a 94-kb PAI, designated ICEPm1, that is common to Proteus mirabilis, Providencia stuartii, and Morganella morganii. These organisms are highly prevalent etiologic agents of catheter-associated urinary tract infections (caUTI), the most common hospital acquired infection. ICEPm1 carries virulence factors that are important for colonization of the urinary tract, including a known toxin (Proteus toxic agglutinin) and the high pathogenicity island of Yersinia spp. In addition, this PAI shares homology and gene organization similar to the PAIs of other bacterial pathogens, several of which have been classified as mobile integrative and conjugative elements (ICEs). Isolates from this study were cultured from patients with caUTI and show identical sequence similarity at three loci within ICEPm1, suggesting its transfer between bacterial genera. Screening for the presence of ICEPm1 among P. mirabilis colonizing isolates showed that ICEPm1 is more prevalent in urine isolates compared to P. mirabilis strains isolated from other body sites (P<0.0001), further suggesting that it contributes to niche specificity and is positively selected for in the urinary tract.

The Selection of Appropriate Bacterial Strains in Preclinical Evaluation of Infection-Resistant Biomaterials

Implant-related infections are broadly recognized as one of the most serious and devastating complications associated with the use of biomaterials in medical practice. The growing interest and need for the development of implant materials with reduced susceptibility to microbial colonization and biofilm formation has necessitated the development of a series of in vitro and in vivo models for evaluation and preclinical testing. Current technologies provide these investigations with an ample choice of qualitative and quantitative techniques for an accurate assessment of the bioactivity and anti-infective efficacy of any new compound or device. These tests are typically performed using a reference bacterial strain designated as the test or reference strain. Recent molecular epidemiological studies have identified the complex clonal nature of most prevalent etiological agents implicated in implant-associated infections. New information which is continually emerging on the identity and the characteristics of both sporadic and epidemic clones must be considered when selecting a reference. A new emerging requirement is that the strain should be representative of the clones causing clinically relevant infections; they should, therefore, belong to the most prevalent epidemic clones rather than to sporadic ones, which may occur in only 1 out of 200 infections or even fewer. The correct choice of reference strain for preclinical tests is of crucial importance for the clinical significance of the achieved results. In this paper we report our experience and recommendations regarding this issue.

Staphylococcus ENTEROTOXIGÊNICOS EM LEITE E PRODUTOS LÁCTEOS, SUAS ENTEROTOXINAS E GENES ASSOCIADOS: REVISÃO

Esta revisão de literatura teve como objetivo relatar estudos sobre a ocorrência de Staphylococcus enterotoxigênicos e suas enterotoxinas em leite e produtos lácteos, surtos e casos esporádicos de intoxicação, tipos de enterotoxinas estafilocócicas e seus genes codificadores. Dentre o gênero Staphylococcus, S. aureus é a espécie contaminante de maior prevalência em leite e queijos, principalmente queijos artesanais e está freqüentemente associada com surtos de intoxicação alimentar. As vias de contaminação de queijos podem ser o leite, o manipulador e o ambiente de processamento. Causa relevante de contaminação do leite cru é a mastite bovina, que tem S. aureus como o principal agente etiológico. Já foram identificados 18 tipos de enterotoxinas (A, B, C1, 2, 3, D, E, G, H, I, J, K, L, M, N, O, P, Q, R e U) e descritos seus respectivos genes. Relatos de ocorrência de cepas coagulase negativa com potencial enterotoxigênico em leite e produtos lácteos indicam a necessidade de reavaliação dos padrões microbiológicos estabelecidos pela legislação brasileira.

Utilization of an Intracellular Bacterial Community Pathway inKlebsiella pneumoniaeUrinary Tract Infection and the Effects of FimK on Type 1 Pilus Expression

Klebsiella pneumoniae is an important cause of urinary tract infection (UTI), but little is known about its pathogenesis in vivo. The pathogenesis of the K. pneumoniae cystitis isolate TOP52 was compared to that of the uropathogenic Escherichia coli (UPEC) isolate UTI89 in a murine cystitis model. Bladder and kidney titers of TOP52 were lower than those of UTI89 at early time points but similar at later time points. TOP52, like UTI89, formed biofilm-like intracellular bacterial communities (IBCs) within the murine bladder, albeit at significantly lower levels than UTI89. Additionally, filamentation of TOP52 was observed, a process critical for UTI89 evasion of neutrophil phagocytosis and persistence in the bladder. Thus, the IBC pathway is not specific to UPEC alone. We investigated if differences in type 1 pilus expression may explain TOP52's early defect in vivo. The type 1 pilus operon is controlled by recombinase-mediated (fimE, fimB, and fimX) phase variation of an invertible promoter element. We found that K. pneumoniae carries an extra gene of unknown function at the 3' end of its type 1 operon, fimK, and the genome lacks the recombinase fimX. A deletion mutant of fimK was constructed, and TOP52 Delta fimK had higher titers and formed more IBCs in the murine cystitis model than wild type. The loss of fimK or expression of E. coli fimX from a plasmid in TOP52 resulted in a larger phase-ON population and higher expression levels of type 1 pili and gave TOP52 the ability to form type 1-dependent biofilms. Complementation with pfimK decreased type 1 pilus expression and biofilm formation of TOP52 Delta fimK and decreased UTI89 biofilm formation. Thus, K. pneumoniae appears programmed for minimal expression of type 1 pili, which may explain, in part, why K. pneumoniae is a less prevalent etiologic agent of UTI than UPEC.

Levantamento sobre a infecção na inserção do cateter de duplo lúmen

OBJETIVO: Identificar o índice de infecção, o agente etiológico, as complicações infecciosas e o tempo de permanência do cateter de duplo lúmen em um mesmo período em anos alternados. MÉTODOS: Trata-se de um estudo retrospectivo realizado no Centro de Hemodiálise do Hospital de Base de São José do Rio Preto-SP, e foram incluídos todos os pacientes com infecção no local de inserção do cateter de duplo lúmen. RESULTADOS: Dos 80 pacientes em tratamento hemodialítico no primeiro período de janeiro a junho de 2002, 21% eram portadores de cateter e três anos depois dos 186 pacientes nas mesmas condições, 10,7% apresentavam terapia por cateter. Houve diminuição de infecções da corrente sangüínea de 9,4% no último período. A complicação infecciosa mais freqüente foi a bacteremia, e o agente etiológico mais encontrado o Staphylococcus aureus, o tempo médio de permanência do cateter foi de 43 dias nos dois períodos avaliados. CONCLUSÃO: Este estudo demonstrou que houve melhora significativa quanto aos índices de infecção nessa população.

Health care-related infections in solid organ transplants

The health care-related infections are well-known in a critical care setting, but reports of those infections in solid organ transplanted patients are scarce. We developed a study of retrospective cohort in a tertiary teaching hospital for 14 months. Eighty-one patients underwent solid organ transplants. The global incidence of health care-related infection was 42.0%. Fifteen percent of the cases were occurrences of surgical site infections, 14.0% pneumonias, 9.0% primary blood stream infections, 4.0% urinary tract infections and 2.0% skin infection. The most prevalent etiologic agents were K. pneumoniae (8.6%), P. aeruginosa (7.4%); A. baumannii (5.0%) and S. aureus (2.5%). Mortality was 18.0%, none of then related to health care infections. The high rate of those infections, mainly surgical site infections, suggests a demand for stricter measures to prevent and control health care-related infections.

Cytotoxic and cytokine-inducing properties of Candida glabrata in single and mixed oral infection models

Oral candidiasis is a common opportunistic infection, with Candida albicans being the most prevalent etiologic agent and Candida glabrata emerging as an important pathogen. C. glabrata is frequently co-isolated with C. albicans from oral lesions. Although C. albicans has been shown to trigger significant cytokine responses and cell damage, C. glabrata has not been systematically studied yet. The purpose of this study was to characterize the ability of C. glabrata to induce proinflammatory cytokine responses and host damage as a single infecting organism and in combination with C. albicans, using in vitro models of the oral mucosa. In monolayer oral epithelial cell cultures, C. glabrata failed to induce a significant interleukin-1 α and interleukin-8 cytokine response and showed lower cytotoxicity, compared to C. albicans. However, C. glabrata triggered a significantly higher granulocyte macrophage colony stimulating factor response than C. albicans. C. glabrata strains showed a strain-dependent tissue damaging ability and a superficial invasion of the mucosal compartment in a three-dimensional (3-D) in vitro model of the human oral mucosa and submucosa. In the 3-D system, co-infection failed to promote host damage beyond the levels of infection with C. albicans alone. These studies indicate that C. glabrata induces cytokines in human oral epithelium in a strain-specific manner, but its tissue/cell damaging ability, compared to C. albicans, is low. Synergy between C. glabrata and C. albicans in cytokine induction and host damage was not observed with the strains tested.

Diagnosis of Human Metapneumovirus Infection in Immunosuppressed Lung Transplant Recipients and Children Evaluated for Pertussis

Human metapneumovirus (hMPV) is a recently discovered paramyxovirus that is known to cause respiratory tract infections in children and immunocompromised individuals. Given the difficulties of identifying hMPV by conventional culture, molecular techniques could improve the detection of this virus in clinical specimens. In this study, we developed a real-time reverse transcription-PCR (RT-PCR) assay designed to detect the four genetic lineages of hMPV. This assay and a commercial real-time nucleic acid sequence-based amplification (NASBA) assay (bioMérieux, Durham, NC) were used to determine the prevalence of hMPV in 114 immunosuppressed asymptomatic and symptomatic lung transplant recipients and 232 pediatric patients who were being evaluated for pertussis. hMPV was detected in 4.3% of the immunosuppressed lung transplant recipients and in 9.9% of children evaluated for pertussis. Both RT-PCR and NASBA assays were efficient in detection of hMPV infection in respiratory specimens. Even though hMPV was detected in a small number of the lung transplant recipients, it was still the most prevalent etiologic agent detected in patients with respiratory symptoms. In both of these diverse patient populations, hMPV infection was the most frequent viral respiratory tract infection identified. Given our findings, infection with hMPV infection should be determined as part of the differential diagnosis of respiratory illnesses.

Severe Pneumonia and Human Bocavirus in Adult

Severe Pneumonia and Human Bocavirus in Adult

Enterovirus meningitis in Brazil, 1998–2003

Acute viral infections of the central nervous system (CNS) such as acute flaccid paralysis, meningitis, and encephalitis, are responsible for a high morbidity, particularly in children. Non-Polio enteroviruses (NPEV) are known to be responsible for over 80% of viral meningitis in which the etiologic agent is identified. In the present study, we show the frequency of enterovirus meningitis in Brazil from December 1998 to December 2003. Enterovirus were isolated from 162 (15.8%), of a total of 1,022 cerebrospinal fluid (CSF) specimens analyzed. Echovirus 30 was identified in 139 of these isolates (139/162-85.2%). Other identified enteroviruses were: Coxsackievirus B5 (3.7%), Echovirus 13 (3.7%), Echovirus 18 (3%), Echovirus 6 (1.2%), Echovirus 25 (1.2%), Echovirus 1 (0.6%), and Echovirus 4 (0.6%). Patients's age ranged from 28 days to 68 years old. The most frequent symptoms were fever (77%), headache (69.5%), vomiting (71.3%), neck stiffness (41.3%), convulsion (7.1%), and diarrhea (3.7%). Although, the majority of the patients recovered without any complication or permanent squeal, five deaths occurred. Throughout the surveillance period, five viral meningitis outbreaks were confirmed: four in the Southern Brazil and one in the Northeast Brazil. Echovirus 30 was responsible for four out of the five outbreaks while Echovirus 13 caused the fifth one. Besides the outbreaks, 734 sporadic cases were also identified during the study period and 59 of these were positive for virus isolation (8%). Echovirus 30 accounted for 70% of the isolates. Our results showed that Echovirus 30 was the most prevalent etiological agent of viral meningitis in Brazil, causing both outbreaks and sporadic cases.

Prevalence of Dermatophytic Fungal Infections in Children: A Recent Study in Anambra State, Nigeria

We conducted a recent survey of dermatological fungal infections amongst children in both urban and rural parts of Anambra State in the south-east geographical flank of Nigeria during the period January 2003 to December 2003. Samples were collected from 1624 children with clinically suggestive lesions and also between the ages of 4 and 16. Young children aged 7-11 and 4- 6 years had significantly higher incidences (P < 0.05) than their older colleagues aged 12-16 years among samples proved to be mycologically positive by microscopy, culture or both. There was a significant difference in the incidence of dermatophytoses amongst children in urban and rural areas investigated (P < 0.05). Tinea capitis was the predominant clinical type. Trichophyton tonsurans was the most prevalent etiological agent while Microsporum audouinii was the least in occurrence. We compared our result with a recent study in the northern geographical zone and observed that although incidence of dermatophytoses is higher in northern Nigeria, tinea capitis was the predominant clinical type in both regions. In addition, the etiological agents appear to vary from time to time in their occurrence and the reasons for these observations are discussed. A regular surveillance and assessment of the etiologic agent and its prevalence by medical mycologists is strongly recommended to facilitate monitoring, reduce/prevent transmission and spread of dermatophytes in countries like Nigeria where they constitute a public health problem.

A prospective study of canine infective endocarditis in northern California (1999-2001): emergence of Bartonella as a prevalent etiologic agent.

A prospective study was performed (June 1999 to May 2001) to determine the incidence of infective endocarditis (IE) due to Bartonella in dogs in northern California and to compare these patients with other dogs with IE. IE was diagnosed antemortem based on clinical signs and echocardiography in 18 dogs. The etiologic agent was Bartonella sp. in 5 dogs (28%) and was diagnosed by high seroreactivity to Bartonella (titer > 1:512; range, 1:1,024-1:4,096); and confirmed postmortem by positive polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) from the infected valve and partial DNA sequencing of the citrate synthase gene (glt A). Conventional bacteria were causative agents in 7 dogs (39%). An etiologic agent was not identified in 6 dogs (33%). Bartonella vinsonii berkhoffii (n = 3), B clarridgeiae (n = 1), and a B clarridgeiae-like organism (n = 1) were identified. Blood culture was positive only for the IE case due to B clarridgeiae. All dogs with IE due to Bartonella were also seroreactive to Anaplasma phagocytophilum. All dogs with IE due to Bartonella had lesions only on the aortic valve. Of the cases of IE not due to Bartonella, 31% involved the aortic valve, 61% the mitral valve, and 8% both valves. Dogs with mitral valve IE lived longer than all dogs with aortic valve IE (P = .004) and dogs with IE of the aortic valve due to Bartonella (P = .002). In conclusion, Bartonella is a common cause of IE in dogs of northern California. A high Bartonella serologic titer (> 1:512) is useful antemortem to diagnose aortic valve IE due to Bartonella.

A Prospective Study of Canine Infective Endocarditis in Northern California (1999–2001): Emergence of Bartonella as a Prevalent Etiologic Agent

A prospective study was performed (June 1999 to May 2001) to determine the incidence of infective endocarditis (IE) due toBartonellain dogs in northern California and to compare these patients with other dogs with IE. IE was diagnosed antemortem based on clinical signs and echocardiography in 18 dogs. The etiologic agent wasBartonellasp. in 5 dogs (28%) and was diagnosed by high seroreactivity toBartonella(titer&gt;1:512; range, 1: 1,024‐1:4,096); and confirmed postmortem by positive polymerase chain reaction (PCR)‐restriction fragment length polymorphism (RFLP) from the infected valve and partial DNA sequencing of the citrate synthase gene (glt A).Conventional bacteria were causative agents in 7 dogs (39%). An etiologic agent was not identified in 6 dogs (33%).Bartonella vinsonii berkhoffii(n = 3),B clarridgeiae(n = 1), and aB clarridgeiae‐likeorganism (n = 1) were identified. Blood culture was positive only for the IE case due toB clarridgeiae.All dogs with IE due toBartonellawere also seroreactive toAnaplasma phagocytophilum.All dogs with IE due toBartonellahad lesions only on the aortic valve. Of the cases of IE not due toBartonella,31% involved the aortic valve, 61% the mitral valve, and 8% both valves. Dogs with mitral valve IE lived longer than all dogs with aortic valve IE (P= .004) and dogs with IE of the aortic valve due toBartonella(P= .002). In conclusion,Bartonellais a common cause of IE in dogs of northern California. A highBartonellaserologic titer (&gt;1:512) is useful antemortem to diagnose aortic valve IE due toBartonella.

Community-acquired pneumonia--pathogens and assessment

Pneumonia is one of the most important infectious diseases, both in terms of incidence as well as potential severity. Streptococcus pneumoniae remains the most prevalent etiologic agent, accounting for about two-thirds of bacteremic cases. Diagnostic procedures include chest radiography, blood culture, Gram staining and culture of expectorated sputum, urine antigen assays for Legionella pneumophila and pneumococci, and asservation of an initial serum sample for comparative serologic investigations. Molecular biology techniques continue to gain importance for the diagnosis of Chlamydia pneumoniae, Mycoplasma pneumoniae, Legionellae and viral respiratory infections, however, their availability at present is mainly restricted to research and reference laboratories.

Epidemiology of swine trichinellosis in the Republic of Croatia.

In order to study the epidemiology of trichinellosis with special emphasis on swine a detailed study was performed. The goals of the study were to define the prevalence of trichinellosis in swine and rats and to determine the etiological agents of the disease with special emphasis on sylvatic species, Trichinella britovi. Considering the obtained data it can be concluded that the risk of Trichinella infection for swine in endemic areas in Croatia is rather high today. On the contrary, a sharp decline in human cases is registered what is certainly a result of obligatory trichinelloscopy even for private purposes. The parasite was found to be prevalent in rats too. Studies on genotypes suggest that Trichinella spiralis is the most prevalent etiological agent of domestic trichinellosis in Croatia, even so the sylvatic species Trichinella britovi can be also present in the domestic habitat suggesting a link between the sylvatic and domestic cycle.

Etiology of dermatophytoses amongst children in northeastern Nigeria.

A survey of dermatophytoses was carried out amongst primary school children in Borno State, Nigeria, during February 1997 to January 1998. A total of 2,193 children aged 4-16 years were screened. Out of these, 154 (7.0%) were proved to be mycologically positive by microscopy, culture or both. Incidence was significantly higher (P <0.05) in young children aged 7-11 years (8.1%) and 4-6 years (6.9%) than in older children aged 12-16 years (3.6%). There was a significant difference in the incidence of dermatophytoses amongst children in urban and rural areas (P <0.05). Tinea capitis was the predominant clinical type followed by tinea corporis. Trichophyton schoenleinii was the most prevalent etiological agent (28.1%), followed by T. verrucosum (20.2%) and Microsporum gallinae (18.4%). Other species recovered included T. mentagrophytes (16.7%), T. tonsurans (10.5%), T. yaoundei (4.4%) and M. gypseum (1.8%).

Endocarditis due to rare and fastidious bacteria.

The etiologic diagnosis of infective endocarditis is easily made in the presence of continuous bacteremia with gram-positive cocci. However, the blood culture may contain a bacterium rarely associated with endocarditis, such as Lactobacillus spp., Klebsiella spp., or nontoxigenic Corynebacterium, Salmonella, Gemella, Campylobacter, Aeromonas, Yersinia, Nocardia, Pasteurella, Listeria, or Erysipelothrix spp., that requires further investigation to establish the relationship with endocarditis, or the blood culture may be uninformative despite a supportive clinical evaluation. In the latter case, the etiologic agents are either fastidious extracellular or intracellular bacteria. Fastidious extracellular bacteria such as Abiotrophia, HACEK group bacteria, Clostridium, Brucella, Legionella, Mycobacterium, and Bartonella spp. need supplemented media, prolonged incubation time, and special culture conditions. Intracellular bacteria such as Coxiella burnetii cannot be isolated routinely. The two most prevalent etiologic agents of culture-negative endocarditis are C. burnetti and Bartonella spp. Their diagnosis is usually carried out serologically. A systemic pathologic examination of excised heart valves including periodic acid-Schiff (PAS) staining and molecular methods has allowed the identification of Whipple's bacillus endocarditis. Pathologic examination of the valve using special staining, such as Warthin-Starry, Gimenez, and PAS, and broad-spectrum PCR should be performed systematically when no etiologic diagnosis is evident through routine laboratory evaluation.