Exophiala dermatitidis

Exophiala is a genus comprising several species of opportunistic black yeasts, which belongs to Ascomycotina. It is a rare cause of fungal infections. However, infections are often chronic and recalcitrant, and while the number of cases is steadily increasing in both immunocompromised and immunocompetent people, detailed knowledge remains scarce regarding infection mechanisms, virulence factors, specific predisposing factors, risk factors, and host response. The most common manifestations of Exophiala infection are skin infections, and the most frequent type of deep infection is pulmonary infection due to inhalation. The invasive disease ranges from cutaneous or subcutaneous infection to systemic dissemination to internal organs. The final identification of the causative organism should be achieved through a combination of several methods, including the newly introduced diagnostic analysis, matrix-assisted laser desorption/ ionization-time-of-flight mass spectrometry, together with sequencing of the ribosomal ribonucleic acid internal transcribed spacer region of the fungi, and histological and culture findings. Regarding treatment, because anti-infective agents and natural compounds exhibited poor antibiofilm activity, few treatments have ultimately been found to be effective for specific antifungal therapy, so the optimal antifungal therapy and duration of therapy for these infections remain unknown. Therefore, most forms of disease caused by Exophiala dermatitidis require aggressive combination therapies: Both surgical intervention and aggressive antifungal therapy with novel compounds and azoles are necessary for effective treatment.     

Amplification of the DNA polymerase I gene of Treponema pallidum from whole blood of persons with syphilis

Previous reports suggest that Treponema pallidum bacteremia occurs in persons with syphilis exposure (‘incubating syphilis’) and in persons with primary or secondary syphilis. During a recent syphilis outbreak, whole blood samples from 32 persons with suspected syphilis or syphilis exposure were screened using polymerase chain reaction (PCR) to amplify the DNA polymerase I gene (polA) of T. pallidum. Of the 32 samples, polA was amplified from 13 (41%). Of these 13, three were determined to have incubating syphilis; two had primary or secondary syphilis and eight had latent syphilis. This study demonstrates that spirochetemia can occur throughout the course of T. pallidum infection.     

Sepsis in a renal transplant recipient due to Citrobacter braakii

Cellulitis is usually caused by organisms such as beta-hemolytic streptococci and Staphylococcus aureus. Citrobacter are gram-negative bacilli that can cause opportunistic infections in immunocompromised hosts. They are rarely implicated in skin or soft tissue infections. The genus Citrobacter has been respeciated according to genetic relatedness. Citrobacter braakii refers to the genomospecies 6 of the Citrobacter freundii complex. There are no detailed studies of infections caused by the newly formed specific genetic species. We report a case of C. braakii infection in a renal transplant patient receiving immunosuppressive therapy. The patient's lower extremity cellulitis did not respond to conventional antibiotic therapy. Blood cultures grew C. braakii. Sensitivity studies and treatment with appropriate antibiotics resulted in prompt recovery. Immunosuppressive therapy in renal transplant recipients predisposes to infection by unusual pathogens, and this should be suspected when lack of a clinical response to conventional antibiotics is observed. We believe this is the first reported case of C. braakii cellulitis and bacteremia in a renal transplant recipient.     

Review of piperacillin/tazobactam in the treatment of bacteremic infections and summary of clinical efficacy

One method of resistance to beta-lactam antimicrobials involves production of beta-lactamases, enzymes that render the beta-lactam ineffective. Beta-lactamase inhibitors have been combined with beta-lactam antibiotics to combat beta-lactamase producing organisms. One such agent, piperacillin/tazobactam, has been shown to be safe and effective therapy for infections usually treated with a combination of antibiotics such as polymicrobial and nosocomial infection, and has been used for empiric therapy in cases of serious infection. A survey of the literature shows that piperacillin/tazobactam is a safe and efficacious therapy for bacteremia as well as soft tissue, intra-abdominal, and lower respiratory tract infections. When combined with an aminoglycoside, it is also useful in the treatment of severe nosocomial respiratory infections.     

Review of piperacillin/tazobactam in the treatment of bacteremic infections and summary of clinical efficacy

One method of resistance to beta-lactam antimicrobials involves production of beta-lactamases, enzymes that render the beta-lactam ineffective. Beta-lactamase inhibitors have been combined with beta-lactam antibiotics to combat beta-lactamase producing organisms. One such agent, piperacillin/tazobactam, has been shown to be safe and effective therapy for infections usually treated with a combination of antibiotics such as polymicrobial and nosocomial infection, and has been used for empiric therapy in cases of serious infection. A survey of the literature shows that piperacillin/tazobactam is a safe and efficacious therapy for bacteremia as well as soft tissue, intra-abdominal, and lower respiratory tract infections. When combined with an aminoglycoside, it is also useful in the treatment of severe nosocomial respiratory infections.A portion of the data presented herein have been presented previously by Dr. Wise at the 17th International Congress of Chemotherapy, Berlin, 1991     

Ultrasound markers of fetal infection, Part 2: Bacterial, parasitic, and fungal infections

Up to 1% of all pregnancies have clinically overt intra-amniotic bacterial infections, and an even larger percentage of pregnant women may be affected by silent infections. Although most pregnant women with overt intra-amniotic bacterial infection have experienced prolonged rupture of membranes (PROM), symptomatic and most silent nonviral intra-amniotic infections may occur with intact membranes. The etiology of intra-amniotic infection after PROM is almost always polymicrobial and consists of genital tract pathogens, such as group B streptococci, Chlamydia trachomatis, Neisseria gonorrhoeae, mycoplasmas, aerobic Gram-negative bacilli, such as the coliforms, and facultative and anaerobic endogenous organisms, such as peptococci, peptostreptococci, and Bacteroides species. These organisms gain access to the uterine cavity by the ascending route. Organisms such as Treponema pallidum, Listeria monocytogenes, Toxoplasma gondii, trypanosomes, and plasmodia are capable of gaining access to the amniotic cavity by transplacental hematogenous spread, and cause devastating fetal infections. Symptomatic intra-amniotic infection is usually a diagnosis of exclusion. Diagnostic criteria based on both clinical and laboratory findings lack sensitivity and are nonspecific. It is difficult to obtain uncontaminated intra-amniotic samples, especially when there is PROM. The problem is even greater with silent infections. In most cases, fetal infection is suspected after an unexplained and unexpected adverse outcome. Maternal morbidity is increased with intra-amniotic infection; although maternal mortality is extremely rare in developed countries, this is not the case in societies where pregnant women have limited or no access to medical care. Although infected women who are treated early and aggressively with wide-spectrum antibiotics do well, more than 10% of these women develop bacteremia and up to half of them will require cesarean delivery because of poor uterine contractions and arrest of labor. The overwhelming majority of term neonates exposed to intrauterine infection after PROM do well, but up to 30% of these neonates require treatment of neonatal pneumonia or bacteremia. Outcomes for preterm neonates or for neonates who experienced silent fetal infections are more severe. Morbidity and mortality rates in these cases are high, and survivors may have long-term devastating sequelae. The ability to identify ultrasound markers of fetal infection will help clinicians identify etiologic agents with greater accuracy and correlate these infections with specific antepartum and postpartum syndromes. The recognition of markers of intrauterine infection will also reduce unexpected adverse outcomes that result from undiagnosed fetal infections.     

Bacteremia caused by Slackia exigua: A report of two cases and literature review

Slackia exigua is an obligate anaerobic coccobacillus associated with dental infection, but rarely causes extraoral infection. We report two cases of monomicrobial bacteremia caused by S. exigua isolated from two institutions. The first case involved community-acquired bacteremia associated with pleural empyema in a 69-year-old man. The second case involved hospital-acquired bacteremia secondary to postoperative intra-abdominal abscess in a 73-year-old man with primary intestinal diffuse large B-cell lymphoma. S. exigua was finally identified by 16S ribosomal RNA gene sequencing analyses in both cases. In the first case, our attempts to identify the organism using commercial identification kits for anaerobes resulted in inaccurate identification as Gemella morbillorum. However, S. exigua was promptly identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry in the second case. The epidemiology and clinical characteristics of S. exigua extraoral infection remain unclear because of the limitations in accurate identification and because only 19 cases of extraoral S. exigua infection have been reported previously, including four cases of bacteremia. Physicians should focus on this species, which can cause community-acquired infections and spread via various routes even in patients with no comorbidities. Further studies are needed to clarify the clinical characteristics of extraoral S. exigua infections.     

Multiple liver cyst infection caused by Salmonella ajiobo in autosomal dominant polycystic kidney disease

Most Salmonella infections are usually self-limited; however, some cases of enteritis result in bacteremia, and there have been reports of extra-intestinal manifestations. Cyst infections are rare, and few cases have been reported. We report a 77-year-old woman with autosomal dominant polycystic kidney disease (ADPKD) complicated with a multiple liver cyst infection caused by Salmonella ajiobo. The patient was hospitalized for fever, abdominal pain, and diarrhea. The blood culture identified Salmonella sp., but the source of infection was not detected by computed tomography or echography. The patient was initially treated with meropenem followed by fluoroquinolones for 3 weeks; however, her C-reactive protein level was high (10–20 mg/dL) even after the antimicrobial therapy. The patient had a fever again on day 51, and Salmonella sp. was detected again from 2 sets of blood cultures. Despite the antimicrobial treatment, her general condition gradually deteriorated, and she died on day 66. The autopsy revealed that most of the liver had been replaced by cysts. Several cysts filled with pus were detected and Salmonella ajiobo was identified in the pus of the infected cysts.     

Clinical characteristics of vancomycin minimum inhibitory concentration of 2 μg/ml methicillin-resistant <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> strains isolated from patients with bacteremia

Recent studies demonstrated that mortality associated with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia was high when vancomycin was used to treat infections with strains that had a high vancomycin minimum inhibitory concentration (MIC). This study compared several characteristics of vancomycin MIC 2 μg/ml strains isolated from bacteremia with those isolated from infections other than bacteremia. A total of 128 episodes of MRSA bacteremia between 2005 and 2008 were followed-up, and compared with 631 MRSA infections other than bacteremia. The isolation of strains with a 2 μg/ml MIC accounted for 32.0% of isolates from MRSA bacteremia, whereas strains with a 2 μg/ml MIC comprised 9.0% of MRSA isolated from other sites (p < 0.001). The incidence of pneumonia as the source of infection was significantly higher in patients with bacteremia from strains with a 2 μg/ml MIC than in those with ≤1 μg/ml MIC. Prior vancomycin use did not correlate with the isolation of 2 μg/ml strains. The efficacy of glycopeptides as 1st line therapy in patients infected with 2 μg/ml strains was significantly lower than that for patients infected with ≤1 μg/ml strains (30.0 vs. 78.8%, p < 0.001) in bacteremia. In the analysis of infections other than bacteremia, efficacy did not reveal a significant difference according to MIC (69.0 vs. 79.6%, p = 0.109). In bacteremia, mortality was 65.8% in patients with 2 μg/ml strains and 19.5% in patients with ≤1 μg/ml strains (p < 0.001), whereas there was no significant difference in mortality from infections other than bacteremia (10.7 vs. 7.8%, p = 0.617). In multivariate analysis, bacteremia with 2 μg/ml strains, intensive care unit (ICU) stay, and liver cirrhosis were independent risk factors for death in patients with bacteremia, and initial appropriate therapy lowered the risk. Several characteristics such as a higher incidence than at other infection sites, a high incidence of pneumonia as a source of infection, a low success rate of vancomycin therapy, and poor prognosis were confirmed in 2 μg/ml MIC MRSA isolated from bacteremia; however, a low success rate of vancomycin and poor prognosis were not apparent in 2 μg/ml MIC MRSA strains isolated from infections other than bacteremia.     

Successful clearance of catheter-related bloodstream infection by antibiotic lock therapy using ampicillin

OBJECTIVE: To report a case in which ampicillin was used successfully as lock therapy for a central venous intravascular catheter and to discuss the implications of ampicillin used in this modality. CASE SUMMARY: A 14-month-old girl with a long-term central venous catheter acquired a polymicrobial (Escherichia coli and Enterococcus durans) bloodstream infection. The central venous catheter was suspected as the source for the bacteremia based on the timing and number of positive blood cultures in relation to therapy with antibiotics. Antibiotic sensitivity testing revealed ampicillin monotherapy to be an ideal choice to treat both organisms. A combination of systemic therapy via a temporary catheter and antibiotic lock therapy of the central venous catheter was then instituted using ampicillin without anticoagulants. The patient tolerated this therapy without complications, and follow-up cultures demonstrated effective clearance of the bacteria. DISCUSSION: Antibiotic lock therapy has been shown to be useful in the treatment of catheter-related bloodstream infections. However, many antibiotics have yet to be tested with this modality. Ampicillin, which is frequently used in the treatment of Enterococcus and E. coli infections, has not previously been reported as a single agent for lock therapy. CONCLUSIONS: Ampicillin may be a useful agent with the relatively new modality of lock therapy for central venous catheters. Further studies are needed to demonstrate possible compatibility of this agent with anticoagulants, such as heparin, as well as its efficacy in treating catheter-related bloodstream infections.     

Mycobacterium wolinskyi: a case series and review of the literature

Mycobacterium wolinskyi is an uncommonly encountered rapidly growing mycobacterium. To date, only 12 clinical cases have been reported in the literature. In this report, we describe 5 additional cases of M. wolinskyi infection seen at the Mayo Clinic in Rochester, MN, since 2009. The clinical manifestations were sternal wound infections (n = 2), a surgical site wound infection, a cardiac-device pocket site infection, and a vascular graft infection with bacteremia. The infections occurred in both immunocompetent and immunosuppressed patients, including a lung transplant recipient. Treatment of M. wolinskyi infections required a prolonged course of combination antimicrobial treatment and surgical debridement.     

Doit-on utiliser la décontamination cutanée par la chlorhexidine en réanimation ?

Prevention of health care-associated infection is a major concern in the intensive care unit. Bacterial skin colonization often precedes occurrence of these infections, especially infections related to staphylococcus species. Chlorhexidine is a topical bactericidal antiseptic with a good antimicrobial activity against Gram positive cocci, fungi but a limited activity against Gram negative rods. Daily chlorhexidine bathing may reduce the occurrence of nosocomial infection by decreasing skin bacterial load. The first observational studies have reported a decrease in skin colonization with staphylococcal or enterococcal species. A decrease in the rate of catheter-related bacteremia and primitive bacteremia has been also described. Multicenter randomized studies have reported a lower incidence of bacteremia caused by coagulase-negative staphylococci. Chlorhexidine bathing was not associated with a lower occurrence of ventilator-associated pneumonia and nosocomial urinary tract infections. This procedure was not associated with a lower incidence of infections caused by Gram negative bacilli. If the use of chlorhexidine bathing for a few months was not associated with acquisition of resistance, increase in the minimal inhibitory concentrations has been described for staphylococci. Daily chlorhexidine bathing could be recommended in units where incidence of staphylococcal blood stream infections remains high.     

Bacteremia in childhood

Review of the bacteriology records of a University Hospital pediatric service for a 30-month period revealed 42 patients with Hemophilus influenzae type b bacteremia and 30 patients with Streptococcus pneumoniae bacteremia, all under age 10. Eighty-eight percent of the Hemophilus bacteremias and 7% of the pneumococcal bacteremias occurred in children less than 2 years of age. Hemophilus bacteremia was seen mot frequently in the first year of life, in contrast to pneumococcal bacteremia which was seen evenly throughout the first and second years of life. In all but one of the Hemophilus infections, a definite source of the bacteremia was apparent; these included CNS infection (58%), cellulitis (14%), and pneumonia (12%). In contrast, no obvious source was apparent in 37% of the pneumococcal bacteremias. When a focus for pneumococcal bacteremia was identified, otitis media and pneumonia were the most frequent diagnoses. Most of the occult pneumococcemias were transient; the results of repeat blood cultures before a treatment decision were helpful in determining the necessity for and duration of antibiotic therapy in those patients with no obvious source of infection.     

Bacterial and Clinical Characteristics of Health Care- and Community-Acquired Bloodstream Infections Due to Pseudomonas aeruginosa

Health care-associated infections, including Pseudomonas aeruginosa bloodstream infection, have been linked to delays in appropriate antibiotic therapy and an increased mortality rate. The objective of this study was to evaluate intrinsic virulence, bacterial resistance, and clinical outcomes of health care-associated bloodstream infections (HCABSIs) in comparison with those of community-acquired bloodstream infections (CABSIs) caused by P. aeruginosa. We conducted a retrospective multicenter study of consecutive P. aeruginosa bacteremia patients at two university-affiliated hospitals. Demographic, clinical, and treatment data were collected. Microbiologic analyses included in vitro susceptibility profiles and type III secretory (TTS) phenotypes. Sixty CABSI and 90 HCABSI episodes were analyzed. Patients with HCABSIs had more organ dysfunction at the time of bacteremia (P = 0.05) and were more likely to have been exposed to antimicrobial therapy (P < 0.001) than those with CABSIs. Ninety-two percent of the carbapenem-resistant P. aeruginosa infections were characterized as HCABSIs. The 30-day mortality rate for CABSIs was 26% versus 36% for HCABSIs (P = 0.38). The sequential organ failure assessment score at the time of bacteremia (hazard ratio [HR], 1.2; 95% confidence interval [CI], 1.1 to 1.3) and the TTS phenotype (HR 2.1; 95% CI, 1.1 to 3.9) were found to be independent predictors of the 30-day mortality rate. No mortality rate difference was observed between CABSIs and HCABSIs caused by P. aeruginosa. Severity of illness and expression of TTS proteins were the strongest predictors of the 30-day mortality rate due to P. aeruginosa bacteremia. Future P. aeruginosa bacteremia trials designed to neutralize TTS proteins are warranted.     

Predictors of mortality in multidrug-resistant Klebsiella pneumoniae bloodstream infections

The dramatic increase of antibiotic resistance in Klebsiella pneumoniae has been associated with fatal outcomes. First, bloodstream infections (BSIs) caused by extended-spectrum β-lactamases (ESBL) Enterobacteriaceae have been associated with treatment failure, more recently BSIs caused by carbapenem-resistant K. pneumoniae (CR-KP) have been reported to be fatal in approximately 50% of cases. Severity of underlying disease, intensive care unit stay at infection onset, infection with ESBL or CR-KP strain and delay in administration of appropriate therapy are among the most common risk factors for mortality in patients with K. pneumoniae BSI, while infection source control and early appropriate antimicrobial treatment have been associated with survival. Thus, risk assessment for ESBL and/or CR-KP is mandatory in patients with suspicion of K. pneumoniae BSI. Here, we examine current evidence regarding risk factors for mortality in patients with K. pneumoniae BSI and address the issue of a risk prediction model for CR-KP BSI.     

Agrobacterium radiobacter and CDC group Ve-2 bacteremia

Agrobacterium radiobacter and CDC Group Ve-2 are rare human pathogens. The simultaneous infection with both of these bacteria in an immunocompromised host is reported. Review of the UCLA microbiology laboratory records revealed one additional case of A. radiobacter bacteremia and two additional cases of CDC Group Ve-2 bacteremia over a 3-year period. The clinical experience with these organisms is reviewed. Both organisms are opportunistic pathogens with a predilection for patients with foreign bodies in place. Although CDC Group Ve-2 bacteremia may respond to antibiotic therapy alone, the cure of A. radiobacter infections often requires foreign body removal.     

First report of survival in two patients with hematologic malignancy and Stenotrophomonas maltophilia hemorrhagic pneumonia treated with trimethoprim-sulfamethoxazole-based combination antibiotic therapy

Stenotrophomonas maltophilia has become a common cause of opportunistic infections in immunocompromised hosts and critical care patients. The most common disease manifestations are pneumonia and bacteremia, with a mortality ranging from 9% to 60.5% depending of the type of infection and host related underlying risk factors. Patients with hematological malignancies may develop a hemorrhagic pneumonia with a rapidly progressive and universally fatal disease course, despite appropriate treatment with trimethoprim/sulfamethoxazole or combination therapy. We report the first two patients with hematologic malignancies and hemorrhagic pneumonia due to S. maltophilia with successful treatment outcomes after early institution of combination therapy with TMP/SMX, polymyxin, and/or moxifloxacin.     

二代测序与重症感染的病原学诊断：路漫漫且修远

早期适当的抗生素治疗是降低重症感染患者病死率的关键,而正确鉴别病原微生物则是恰当的抗生素治疗的前提条件。然而,对于病原微生物的检测而言,绝大多数传统微生物学方法具有一定的目标性或指向性。当临床医生怀疑多种病原微生物并存时,可能需要同时进行多种微生物学的检查。近年来,二代测序（NGS）技术被应用于某些特殊病原微生物感染的诊治中。然而,作为一种新的实验室诊断技术,现有证据尚不足以支持NGS在临床上的常规应用。     

Epidemiology,Laboratory Detection,and Therapy of Penicillin-resistant Streptococcal Infections

Streptococci cause a wide range of infections in humans including respiratory tract infections, endocarditis, meningitis, bacteremias, and skin and soft tissue lesions. Mutations in the penicillin binding proteins target sites in these organisms have recently caused resistance to penicillins and cephalosporins. The passage of resistant genetic material from one streptococcal species to another has been recognized as one of the mechanisms by which this resistance has occurred and spread. Such resistance has been a particular problem in Streptococcus pneumoniae and viridans group streptococci with penicillin resistance levels in excess of 25%, now common in both groups of organisms worldwide. Fourth-generation cephalosporins, with their enhanced antibacterial activity against Gram-positive organisms (cefpirome > cefepime) and their increased stability to the β-lactamases produced by many bacterial species, offer a new option for the treatment of potentially life-threatening infections such as pneumococcal pneumonia and meningitis with or without bacteremia. Clinical trials are currently in place to evaluate the role of these agents in these, and other, indications of Gram-positive infections. Prior studies of cefpirome therapy for infections caused by Streptococcus spp. were successful, and recent expanded in vitro investigations profess a future for expanded use of cefpirome to treat infections produced by several Gram-positive species.     

Moraxella lacunata infection associated with septicemia,endocarditis, and bilateral septic arthritis in a patient undergoing hemodialysis: A case report and review of the literature

We report the first case of both endocarditis and bilateral septic arthritis in a patient caused by Moraxella lacunata and successful management of the infection with antimicrobial therapy. The route of entry leading to bacteremia may have been the oral cavity given the poor oral hygiene of the patient as evidenced by bleeding gums. We hypothesize that the bacteremia led to septic arthritis and mitral valve infective endocarditis. In this case report, we also review the literature on M. lacunata infections and conclude that this organism should be considered in bilateral septic arthritis in a patient with underlying heart abnormalities and/or with renal failure.