Osteomyelitis due to Veillonella parvula: case report and review.

Anaerobic gram-negative cocci of the genus Veillonella are generally normal flora of the oropharynx and upper respiratory tract. When isolated in clinical specimens, these bacteria are usually regarded as commensal organisms rather than as pathogens. We report a case of spinal osteomyelitis in which Veillonella parvula was isolated in pure culture from bone as well as blood. Osteomyelitis of the spine due to anaerobic bacteria may occur more frequently than has been recognized, and anaerobic cultures of biopsy specimens should be routinely performed.     

Role of antibiotic therapy in diabetic foot management

Antibiotic therapy is not the most important component in diabetic foot ulcer management which should be based on weight bearing avoidance and arterial revascularization. However antibiotic therapy is necessary in presence of extensive deep involvement or systemic signs of infection. Initial antimicrobial treatment depends on bacteria supposed origin. For patients not coming from hospital, the initial choice antibiotic is an amoxicillin/clavulanate agent because it offers optimal coverage for most pathogens involved in those diabetic foot lesions (gram positive cocci, gram negative and anaerobic organisms). For patients at high risk to be infected with nosocomially acquired pathogens, the initial antibiotic therapy must cover methicillin-resistant staphylococci, resistant pseudomonas aeruginosa or enterobacteriae. In all cases, when definitive reliable cultures are reported, initial antibiotic regimens should be revised to narrow the coverage to specific pathogens. In presence of osteomyelitis, a temporary combination of two agents which are known to reach high bone concentrations is necessary, and antibiotic therapy should be continued for at least two months. In other cases, antibiotic treatment duration depends on clinical out come.     

How much do Pseudomonas biofilms contribute to symptoms of pulmonary exacerbation in cystic fibrosis?

Recent studies suggest that chronic Pseudomonas aeruginosa lung infections in cystic fibrosis (CF) involve anaerobic biofilms, and that these biofilms are the reason chronic infections are rarely eradicated by antibiotic therapy, regardless of the in vitro susceptibility of infecting bacteria. These observations led to the development of an in vitro method for testing antibiotic susceptibility of CF clinical isolates in biofilms (Moskowitz et al., J Clin Microbiol 2004;42:1915-1922) and unearthed an apparent paradox. Antibiotics that remain cornerstones of clinical management of CF pulmonary exacerbations (e.g., beta-lactam antibiotics) appear to have little to no activity at clinically achievable concentrations when tested in vitro against clinical P. aeruginosa isolates growing in biofilms. The proven clinical efficacy of beta-lactam antibiotics in treating exacerbations, and the selection for beta-lactam resistance in vivo, suggest that planktonic bacteria play a significant role in pulmonary exacerbations of CF. A model of infection architecture is proposed in which biofilm and planktonic compartments each play a role in infection persistence and pulmonary exacerbation, respectively. Infection architecture may partially account for the observed lack of correlation between in vitro antibiotic susceptibility testing and clinical response to antibiotic therapy.     

The presence of antibody-coated anaerobic bacteria in asymptomatic bacteriuria during pregnancy.

Quantitative anaerobic culture of urine samples obtained from 593 pregnant women by suprapubic bladder aspiration was performed to establish the involvement of anaerobic bacteria in asymptomatic urinary tract infections. The fluorescent antibody (FA) test was applied to the sediments of bladder aspirates to determine the site of infection. Anaerobic bacteriuria (greater than or equal to 10(4) microorganisms/ml of urine) was found in 34 patients, of whom five were FA-positive. These anaerobes were identified as Lactobacillus minutus, Veillonella parvula (two patients). Clostridium putrefaciens, and Peptostreptococcus anaerobius. Aerobic bacteriuria (greater than 10(4) microorganisms/ml of urine) was detected in 27 patients, of whom 13 were FA-positive. In 10 women with mixed aerobic/anaerobic bacteriuria, no FA-positive bacteria were found. The finding of FA-positive anaerobes may indicate that these organisms are involved in silent renal infection.     

Anorectal infections in patients with malignant diseases

Fifty-seven episodes of anorectal infection in 44 patients with malignant diseases primarily leukemia or lymphoma, have been retrospectively reviewed. Seventeen patients died in hospital, but only in seven cases was the anorectal infection a major contributing cause of death. The most important prognostic indicator of outcome was number of days of neutropenia during the infectious episode. Cultures obtained at the time of surgical drainage or by needle aspiration of the wound revealed multiple organisms in 26 of 29 instances, and anaerobic organisms were the commonest isolates. Anorectal infection was controlled in 28 (55%) of 51 treatment courses when antibiotics were the only treatment given. However, if the antibiotic regimen included both an aminoglycoside and an antibiotic with anaerobic coverage, control of infection was observed in 15 (88%) of 17 cases. There were 26 surgical procedures performed, with acceptable morbidity. Infection was controlled in 19 (73%) of 26 cases treated with surgery and antibiotics. The results support managing most of these infections initially with medical treatment, using an antibiotic regimen that includes an aminoglycoside and a specific drug against anaerobes. Surgery is recommended if there is obvious fluctuance, a significant amount of necrotic tissue evident, or progression of the infection locally or continued sepsis after an adequate antibiotic trial.     

Pericarditis due to anaerobic bacteria

This review describes the microbiology, diagnosis and management of pericarditis due to anaerobic bacteria. The predominant anaerobes recovered from patients with pericarditis were: gram-negative bacilli (mostly of the Bacteroides fragilis group), anaerobic streptococci, Clostridium spp., Fusobacterium spp., and Bifidobacterium spp. Anaerobic bacteria can be isolated in pericarditis resulting from the following mechanisms: (1) spread from a contiguous focus of infection, either de novo or after surgery or trauma (pleuropulmonary, esophageal fistula or perforation, and odontogenic); (2) spread from a focus of infection within the heart, most commonly from endocarditis; (3) hematogenous infection, and (4) direct inoculation as a result of a penetrating injury or cardiothoracic surgery. No differences were found in the clinical diagnostic features between cases of pericarditis due to anaerobic bacteria and those due to aerobic and facultative bacteria. Anaerobic gram-negative bacilli have increased their resistance to penicillins and other antimicrobials in the last decade. Complete identification and testing for antimicrobial susceptibility and lactamase production are therefore essential for the management of infections caused by these bacteria. Treatment of pericarditis involving anaerobic bacteria includes the use of antibiotic therapy effective against these organisms.     

Diagnosis and treatment of ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in the ICU. Patients who acquire VAP have higher mortality rates and longer ICU and hospital stays. Because there are other potential causes of fever, leukocytosis, and pulmonary infiltrates, clinical diagnostic criteria are overly sensitive in the diagnosis of VAP. Employing quantitative cultures of bronchopulmonary secretions in the diagnostic algorithm leads to less antibiotic use and probably to lower mortality. With respect to microbiologic diagnosis, it is not clear that the use of a particular sampling method (bronchoscopic or nonbronchoscopic), when quantitatively cultured, is associated with better outcomes. Delayed administration of adequate antibiotic therapy is linked to an increased mortality rate. Hence, the focus of initial antibiotic therapy should be to rapidly provide antibiotic coverage for all likely pathogens and to then narrow or focus the antibiotic spectrum based on the results of quantitative cultures. Eight days of antibiotic therapy appears equivalent to 15 days of therapy except when treating nonlactose-fermenting Gram-negative organisms. In this latter situation, longer treatment durations appear to reduce the risk of recrudescence after discontinuation of antibiotic therapy. A guideline-based approach using the local hospital or ICU antibiogram can increase the likelihood that adequate initial antibiotic therapy is used and reduce the overall use of antibiotics and the associated selection pressure for multidrug-resistant organisms.     

Unilateral leptospiral pneumonia and cold agglutinin disease.

Pneumonia that is unresponsive to appropriate antibiotic therapy suggests an infection due to more unusual or resistant organisms. In this report, a child with unilateral pneumonia, pleural effusion, and anti-I cold hemagglutinin antibodies is presented. The usual causes of this clinical picture were suspected and treated, but the child did not improve. Features of her history suggested a more unusual etiology, and a diagnosis of leptospirosis was made. A brief discussion of leptospiral disease in children is provided.     

The role of anaerobic bacteria in upper respiratory tract and other head and neck infections

Anaerobes are common pathogens in chronic upper respiratory tract and head and neck infections. They can be recovered in chronic otitis media and sinusitis, play a role in tonsillitis, and predominate in complications of these infections, causing deep oral and neck infections and abscesses. In addition to their direct pathogenicity, they play an indirect role through the production of the enzyme β-lactamase, “shielding” non-β-lactamase-producing bacteria from penicillins. Failure to provide adequate therapy against anaerobes may lead to clinical failures. Management of anaerobic infection is complicated by the slow growth of these organisms, by their polymicrobial nature, and by their growing resistance to antimicrobials. Antimicrobials are often the only form of therapy needed, but surgical approach is needed in some cases. Because anaerobes often are mixed with aerobic organisms, the antimicrobials given should provide adequate coverage against all pathogens.     

Disseminated infection with Trichosporon beigelii

Two cases of systemic infection with Trichosporon beigelii are reported. Both patients had acute leukemia and were receiving cytotoxic and antibiotic drug therapy, which included amphotericin B, at the time of sepsis. Although clinical isolates of the organisms were found to be sensitive to amphotericin B in vitro, both patients died from severe, widespread fungal infection. The pathologic findings in these two cases suggest that the host response to trichosporon infection is a granulomatous inflammation. Trichosporon is a virulent opportunistic pathogen that may originate from the gastrointestinal tract damaged by cytotoxic therapy in the patient with aplasia. Despite aggressive antifungal therapy, survival is most closely related to recovery of the host's hematopoietic system.     

Antibiotics in lung abscess.

Anaerobic bacteria are relatively common and important pathogens in the lower airways, but are rarely detected due to problems in obtaining adequate specimens for anaerobic bacterial culture. As a consequence, therapeutic decisions are generally empiric and made on the basis of suspected involvement of these organisms according to various clinical clues. With respect to antibiotic options, there is probably a multitude of drugs that would be effective, but there are only three that have a sufficient experience according to published reports: clindamycin, penicillin, and metronidazole combined with penicillin. Recent studies suggest that many of the bacteria involved in these infections produce beta-lactamase, consequently favoring drugs other than penicillins for these infections. Nevertheless, the in vivo experience continues to be relatively good for penicillin when given for orodental or pulmonary infections involving anaerobes derived from the upper airways. For a serious anaerobic infection, such as putrid abscesses associated with large cavities or severe toxicity, the usual drug recommendation is clindamycin. For less serious infections, regimens with established merit are noted above. It is likely that almost any beta-lactam (other than antistaphylococcal penicillins, ceftazidime, or azthreonam) would be adequate; metronidazole should not be used as a single agent.     

Infections in diabetic foot ulcerations

Diabetic foot complications are the largest nontraumatic cause of lower extremity amputations, accounting for almost 90,000 amputations per year. Most of these amputations are the result of infections caused by ulcerations of the foot that are not recognized or treated in an appropriate and timely fashion. Often, cultures are taken when not warranted and antibiotics are administered when no infection is present, causing significant increases in resistant organisms. Although there have been many attempts to classify diabetic foot lesions, none of these systems are specific for infectious complications. This paper presents a system for identifying the presence and severity of infection with suggestions for appropriate empiric antibiotic therapy.     

Antibiotic resistance of oral anaerobic bacteria and their effect on the management of upper respiratory tract and head and neck infections

Anaerobes of oral origin are common in chronic upper respiratory tract and other head and neck infections. Anaerobes are the predominant components of the normal human oropharyngeal flora, and are therefore a common cause of bacterial infections of the upper respiratory tract that are of endogenous origin. These bacteria can be isolated in chronic otitis media, sinusitis, and tonsillitis, and their complications. Anaerobes also predominate in deep oral and neck infections and abscesses. Their isolation requires appropriate methods of collection, transportation, and cultivation of specimens. In addition to their active pathogenic role in these infections, many anaerobes express an indirect effect through their ability to produce the enzyme beta-lactamase. This enables these organisms to shield non-beta-lactamase-producing bacteria (BLPB) from penicillins. Inadequate therapy against BLPB may lead to clinical failures. Treatment of anaerobic infection is complicated by their slow growth, their polymicrobial nature, and the growing resistance of anaerobic bacteria to antimicrobials. Antimicrobial therapy is often the only form of therapy needed, whereas in other instances it is an important adjunct to a surgical approach. Because anaerobes generally are isolated mixed with aerobic organisms, therapy should provide for adequate coverage of both types of pathogens.     

Prevalence of multiresistant Gram-negative organisms in a surgical hospital in Ho Chi Minh City, Vietnam

OBJECTIVE: To determine resistance patterns of multiresistant Gram-negative organisms at a surgical hospital in Ho Chi Minh City, Vietnam, in order to guide appropriate antibiotic prescribing and improve infection control procedures. METHOD: All samples sent in for microbiological analysis over a 3-month period were included. A resource neutral double disc-diffusion test was introduced to detect the presence of extended-spectrum beta-lactamase (ESBL) production. RESULTS: We obtained 350 bacterial isolates from clinical specimens; 87.4% were Gram-negative bacteria (GNB). Of these, 88.9% were Enterobacteriaceae, of which 14.7% produced ESBL. Fifteen (37.5%) of these were isolated within 48 h of admission. Resistance to gentamicin and ciprofloxacin occurred in 70.0% and 72.5% of those organisms that produced ESBL and in 39.5% and 38.7% of those that did not. Resistance to third-generation cephalosporins was common: 36.7% of all GNB were resistant to ceftriaxone, 34.0% to cefotaxime, 19.6% to ceftazidime and 36.7% to cefoperazone. CONCLUSION: Multiresistant Gram-negative organisms are common and pose a challenge to antibiotic therapy. Successful implementation of a simple test to detect ESBL production allowed reporting of these organisms, appropriate antibiotic prescribing and infection control interventions. Development of antibiotic-prescribing guidelines must take into account these resistance patterns.     

Actinomycetoma masquerading as an abdominal neoplasm

Despite the fact that infection accompanying actinomycotic organisms is relatively rare, the possibility of such infection should be kept in mind because the organism is known to be commensal in the oral cavity, lungs, and intestinal tract. Abdominal lesions may mimic a neoplasm in many ways—physical findings, clinical course, and roentgenographic changes. Since the bacterium is anaerobic and difficult to grow on culture, one may have to rely on histologic confirmation for diagnosis. The infection can usually be eradicated by large doses of antibiotic (penicillin) over an extended period of time.     

Infectious colitis excluding E. coli O157:H7 and C. difficile

Colitic infection caused by a variety of organisms may have an extremely varied presentation, course, and treatment response. Current data have provided great insights into the pathophysiology of these various organisms and their clinical presentation, course, and treatment outcomes. As clinicians develop a better understanding of the colon, its immunologic defense mechanisms, and the virulence factors of such organisms, they will be better able to evaluate these infections as well as newer colonic infections yet unknown. It is important to know if and when to treat such organisms to prevent the dilemma of drug-resistant strains, as seen already in a variety of well-known infections, such as Campylobacter and others. Knowledge of such colonic targets will be more important in an era of ever-growing resistance to and wide use of antibiotic regimens.     

Antimicrobial therapy of febrile complications after high-dose chemo-/radiotherapy and autologous hematopoietic stem cell transplantation--guidelines of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Oncology (DGHO)

Infectious complications occur in 60-100% of patients following high-dose chemotherapy (HDC) and autologous hematopoietic stem cell transplantation (HSCT), and are commonly caused by Gram-negative aerobic bacteria (such as Pseudomonas aeruginosa and enterobacteriacea e) and Gram-positive cocci (such as enterococci, streptococci and staphylococci), which should be covered by empiric first-line antibiotic therapy. Less frequently, infections are caused by fungi and anaerobic bacteria, and initial therapy does not necessarily have to cover coagulase-negative staphylococci, oxacillin-resistant S. aureus (MRSA), anaerobic bacteria and fungi. Patients who already receive antibiotics and develop pulmonary infiltrates should immediately be treated with systemic antifungals. Patients with fever and diarrhea or other signs and symptoms of gastrointestinal or perianal infection should be treated with antibiotics covering anaerobic bacteria and enterococci. Clinically stable patients with skin infections or central venous catheter-related infections can be treated with standard empiric antibiotic therapy including a beta-lactam active against Pseudomonas aeruginosa with or without an aminoglycoside, and should only receive glycopeptides if they do not respond to first-line therapy within 72 hours, become clinically unstable, have severe mucositis, or when resistance against the empiric antibiotics is demonstrated. Recombinant hematopoietic growth factors should not be added routinely but may be considered in life-threatening situations such as invasive pulmonary mycoses or sepsis.     

Asthma and atypical bacterial infection

A growing body of basic and clinical science implicates the atypical bacterial pathogens Mycoplasma pneumoniae and Chlamydophila (formerly Chlamydia) pneumoniae as potentially important factors in asthma, although their exact contribution to asthma development and/or persistence remains to be determined. Evidence from human studies links both M pneumoniae and C pneumoniae to new-onset wheezing, exacerbations of prevalent asthma, and long-term decrements in lung function, suggesting that these organisms can play an important role in the natural history of asthma. Furthermore, animal models of acute and chronic infection with these organisms indicate that they have the ability to modulate allergic sensitization and pulmonary physiologic and immune response to allergen challenge. These findings raise the possibility that, in at least some individuals with asthma, antibiotic therapy might have a role in long-term treatment. While antibiotics do not currently have a defined role in the treatment of stable patients with chronic asthma, there is emerging evidence that asthma symptoms and biomarkers of airway inflammation can improve when patients who have atypical bacterial infection as a cofactor in their asthma are treated with macrolide antibiotics. Ongoing research into the importance of atypical pathogens in asthma will further elucidate whether these infections are important in disease development or whether their prevalence is increased in asthmatic subjects due to chronic airway inflammation or other, yet unidentified, predisposing factors. Current studies will further define the role of macrolide antibiotics in the treatment of stable patients with asthma, ultimately determining whether these therapeutic agents have a place in asthma management.     

Permanent pacemaker infections: Characterization and management

From January 1974 to June 1980, a total of 46 patients were treated for infections involving permanent pacing systems. Demographic characteristics, types of infecting organisms, specific clinical features, significance of an infected foreign body and various medical and surgical treatment methods are described. Likely infecting organisms depend on the mode of presentation and the time course of the infection. Optimal treatment for the large majority of patients requires removal of the entire infected pacing system. In a subgroup of patients, a short course of antibiotic therapy followed by one stage surgery involving Implantation of a new pacing system and concurrent explantation of the infected pacemaker was used safely wlth excellent results.     

Bacteriological study of diabetic foot infections

AIMS: The polymicrobial nature of diabetic foot infection has been well documented in the literature. Patients with diabetic foot infection not exposed to antibiotics are not well studied before. The relative frequency of bacterial isolates cultured from community-acquired foot infections that are not exposed to antimicrobial agents for 30 days is studied. In addition, the bacterial comparative in vitro susceptibility to the commonly used antibacterial agents is assessed. METHODS: This is a prospective study in which the infected wounds of 86 consecutive diabetic patients seen in the diabetic foot clinic in Adan Teaching Hospital were cultured when visiting the clinic. The patients did not receive antimicrobial therapy 30 days prior to taking the cultures. The specimen was cultured using aerobic and anaerobic microbiological techniques. Isolates were tested for susceptibility to commonly used antimicrobial therapy. RESULT: Staphylococcus aureus was the most common isolate, being recovered from 38.4% of cases. Other organisms were Pseudomonas aeruginosa (17.5%) and Proteus mirabilis (18%), anaerobic gram-negative organisms (10.5%), mainly Bacteroides fragilis. Imipenem, meropenem, and cefepime were the most effective agents against gram-negative organisms. Vancomycin was the most effective against gram-positive organisms. CONCLUSION: S. aureus and P. aeruginosa were the most common causes of diabetic foot infections. Anaerobic organisms are still a common cause for infection, although the prevalence is less. These wounds may require use of combined antimicrobial therapy for initial management.