Community-associated methicillin-resistant Staphylococcus aureus endocarditis 'down under': case series and literature review.

Infective endocarditis is a common complication of Staphylococcus aureus bacteraemia, but literature reports of community-associated methicillin-resistant S. aureus (CA-MRSA) endocarditis are relatively uncommon and mostly comprise intravenous drug users (IVDUs) with the USA300 strain. We report 5 cases of CA-MRSA endocarditis in previously healthy young Australian adults, 4 in IVDUs. Morbidity was high with frequent septic emboli; 3 patients required cardiac surgery and 1 patient died. Typing revealed the 2 most common Australian strains, the Panton-Valentine leukocidin (PVL)-positive ST93 (Queensland) strain and the PVL-negative ST1 (WA-MRSA-1) strain.

Escherichia coli isolates causing asymptomatic bacteriuria in catheterized and noncatheterized individuals possess similar virulence properties.

Urinary tract infections (UTIs) are among the most common infectious diseases of humans, with Escherichia coli being responsible for >80% of all cases. Asymptomatic bacteriuria (ABU) occurs when bacteria colonize the urinary tract without causing clinical symptoms and can affect both catheterized patients (catheter-associated ABU [CA-ABU]) and noncatheterized patients. Here, we compared the virulence properties of a collection of ABU and CA-ABU nosocomial E. coli isolates in terms of antibiotic resistance, phylogenetic grouping, specific UTI-associated virulence genes, hemagglutination characteristics, and biofilm formation. CA-ABU isolates were similar to ABU isolates with regard to the majority of these characteristics; exceptions were that CA-ABU isolates had a higher prevalence of the polysaccharide capsule marker genes kpsMT II and kpsMT K1, while more ABU strains were capable of mannose-resistant hemagglutination. To examine biofilm growth in detail, we performed a global gene expression analysis with two CA-ABU strains that formed a strong biofilm and that possessed a limited adhesin repertoire. The gene expression profile of the CA-ABU strains during biofilm growth showed considerable overlap with that previously described for the prototype ABU E. coli strain, 83972. This is the first global gene expression analysis of E. coli CA-ABU strains. Overall, our data suggest that nosocomial ABU and CA-ABU E. coli isolates possess similar virulence profiles.

Virulence properties of asymptomatic bacteriuria Escherichia coli.

In asymptomatic bacteriuria (ABU), bacteria colonize the urinary tract without provoking symptoms. Here, we compared the virulence properties of a collection of ABU Escherichia coli strains to cystitis and pyelonephritis strains. Specific urinary tract infection (UTI)-associated virulence genes, hemagglutination characteristics, siderophore production, hemolysis, biofilm formation, and the ability of strains to adhere to and induce cytokine responses in epithelial cells were analyzed. ABU strains were phylogenetically related to strains that cause symptomatic UTI. However, the virulence properties of the ABU strains were variable and dependent on a combination of genotypic and phenotypic factors. Most ABU strains adhered poorly to epithelial cells; however, we also identified a subgroup of strongly adherent strains that were unable to stimulate an epithelial cell IL-6 cytokine response. Poor immune activation may represent one mechanism whereby ABU E. coli evade immune detection after the establishment of bacteriuria.

Modified measles with an atypical presentation

We report symptomatic confirmed modified measles infection in a person with one documented MMR (measles, mumps, rubella) vaccination and travel to Indonesia. No secondary cases were identified, consistent with other case reports of modified measles infection. The infectivity of modified measles for contact tracing requirements requires further elucidation.

Identification of type 3 fimbriae in uropathogenic Escherichia coli reveals a role in biofilm formation.

Catheter-associated urinary tract infection (CAUTI) is the most common nosocomial infection in the United States. Uropathogenic Escherichia coli (UPEC), the most common cause of CAUTI, can form biofilms on indwelling catheters. Here, we identify and characterize novel factors that affect biofilm formation by UPEC strains that cause CAUTI. Sixty-five CAUTI UPEC isolates were characterized for phenotypic markers of urovirulence, including agglutination and biofilm formation. One isolate, E. coli MS2027, was uniquely proficient at biofilm growth despite the absence of adhesins known to promote this phenotype. Mini-Tn5 mutagenesis of E. coli MS2027 identified several mutants with altered biofilm growth. Mutants containing insertions in genes involved in O antigen synthesis (rmlC and manB) and capsule synthesis (kpsM) possessed enhanced biofilm phenotypes. Three independent mutants deficient in biofilm growth contained an insertion in a gene locus homologous to the type 3 chaperone-usher class fimbrial genes of Klebsiella pneumoniae. These type 3 fimbrial genes (mrkABCDF), which were located on a conjugative plasmid, were cloned from E. coli MS2027 and could complement the biofilm-deficient transconjugants when reintroduced on a plasmid. Primers targeting the mrkB chaperone-encoding gene revealed its presence in CAUTI strains of Citrobacter koseri, Citrobacter freundii, Klebsiella pneumoniae, and Klebsiella oxytoca. All of these mrkB-positive strains caused type 3 fimbria-specific agglutination of tannic acid-treated red blood cells. This is the first description of type 3 fimbriae in E. coli, C. koseri, and C. freundii. Our data suggest that type 3 fimbriae may contribute to biofilm formation by different gram-negative nosocomial pathogens.

Severe photosensitivity causing multifocal squamous cell carcinomas secondary to prolonged voriconazole therapy.

A 32-year-old woman was treated with long-term voriconazole therapy for recurrent aspergillosis associated with chronic granulomatous disease. A short time after commencement of voriconazole therapy, a severe photosensitivity reaction developed. Continued voriconazole exposure led to the development of multifocal facial squamous cell carcinomas. The photosensitivity reaction resolved after the patient changed therapy to posaconazole.

Gastroesophageal reflux disease, acid suppression, and Mycobacterium avium complex pulmonary disease.

BACKGROUND: Weekly symptoms of gastroesophageal reflux disease (GERD) occur in 20% of the population, and GERD has been implicated in the pathophysiology of many respiratory diseases. Microaspiration of contaminated water is a potential portal of entry for Mycobacterium avium complex (MAC) organisms into the respiratory tract, and acid-suppression therapy may enhance the survival of mycobacteria in the stomach. This study aimed to assess the prevalence of GERD, swallowing disorders, reflux symptoms, and acid-suppression therapy in patients with MAC lung disease (MAC positive [MAC+]), and to compare these patients to control subjects without MAC lung disease (MAC negative [MAC-]). METHODS: Clinical information was collected on 58 MAC+ patients and 58 age- and sex-matched MAC- patients who were asked to complete a DeMeester questionnaire of reflux symptoms and to identify any acid-suppressive medication consumed. RESULTS: A clinical diagnosis of GERD was documented in 23 of 52 MAC+ patients (44.2%), compared to 16 MAC- patients (27.6%) [p = 0.019]. MAC+ patients consumed significantly more histamine type 2 receptor antagonists and prokinetic agents, and MAC- patients consumed more antacids. The mean DeMeester questionnaire score (+/- SD) for MAC+ patients was 1.39 +/- 1.8, and for MAC- patients was 0.88 +/- 1.4. (p = 0.098). Aspiration was suspected in nine MAC+ patients (15.5%), compared to three MAC- patients (5.2%) [p = 0.032]. There was no association between GERD and radiologic presentation of MAC disease. Consolidation and nodules > 5 mm were more common in those receiving acid suppression than those who were not. CONCLUSIONS: GERD, acid suppression, and clinically suspected aspiration are more common in patients with MAC lung disease than in similar patients without MAC disease.

Risk factors for urinary catheter associated bloodstream infection.

OBJECTIVES: Urinary catheter associated bloodstream infection (UCABSI) causes significant morbidity, mortality and healthcare costs. We aimed to define the risk factors for UCABSI. METHODS: A case-control study was conducted at two Australian tertiary hospitals. Patients with urinary source bloodstream infection associated with an indwelling urinary catheter (IDC) were compared to controls with an IDC who did not develop urinary source bloodstream infection. RESULTS: There were 491 controls and 67 cases included in the analysis. Independent statistically significant risk factors for the development of UCABSI included insertion of the catheter in operating theatre, chronic kidney disease, age-adjusted Charlson comorbidity index, accurate urinary measurements as reason for IDC insertion and dementia. IDCs were inserted for valid reasons in nearly all patients, however an appropriate indication at 48 h post-insertion was found in only 44% of patients. Initial empiric antibiotics were deemed inappropriate in 23 patients (34%). CONCLUSION: To our knowledge, this is the first study to look specifically at the risk factors for bloodstream infection in urinary catheterised patients. Several risk factors were identified. IDC management and empiric management of UCABSI could be improved and is likely to result in a decreased incidence of infection and its complications.

Intradermal recombinant hepatitis B vaccine for healthcare workers who fail to respond to intramuscular vaccine.

OBJECTIVE: To study the humoral immune responses, safety, and tolerability of intradermal recombinant hepatitis B vaccination in healthcare workers (HCWs) nonresponsive to previous repeated intramuscular vaccination. DESIGN: An open, prospective, before-after trial. SETTING: A tertiary referral hospital and surrounding district health service in Queensland, Australia. PARTICIPANTS: Hospital and community HCWs nonresponsive to previous intramuscular hepatitis B vaccination. METHODS: Intradermal recombinant hepatitis B vaccine was administered every second week for a maximum of 4 doses. Hepatitis B surface antibody (anti-HBs) responses were assessed 2 weeks after each dose. RESULTS: Protective anti-HBs levels developed in 17 (94%) of 18 study subjects. Three doses resulted in seroconversion of all responding subjects and the highest geometric mean antibody concentration. The vaccine was well tolerated. CONCLUSION: More than 90% of previously nonresponsive HCWs responded to intradermal recombinant hepatitis B vaccine with protective anti-HBs levels.

A PCR method for the identification of methicillin-resistant Staphylococcus aureus (MRSA) from screening swabs.

AIM: The aim of this study was to assess the discriminatory power and potential turn around time (TAT) of a PCR-based method for the detection of methicillin-resistant Staphylococcus aureus (MRSA) from screening swabs. METHODS: Screening swabs were examined using the current laboratory protocol of direct culture on mannitol salt agar supplemented with oxacillin (MSAO-direct). The PCR method involved pre-incubation in broth for 4 hours followed by a multiplex PCR with primers directed to mecA and nuc genes of MRSA. The reference standard was determined by pre-incubation in broth for 4 hours followed by culture on MSAO (MSAO-broth). RESULTS: A total of 256 swabs was analysed. The rates of detection of MRSA using MSAO-direct, MSAO-broth and PCR were 10.2, 13.3 and 10.2%, respectively. For PCR, the sensitivity, specificity, positive predictive value and negative predictive values were 66.7% (95%CI 51.9-83.3%), 98.6% (95%CI 97.1-100%), 84.6% (95%CI 76.2-100%) and 95.2% (95%CI 92.4-98.0%), respectively, and these results were almost identical to those obtained from MSAO-direct. The agreement between MSAO-direct and PCR was 61.5% (95%CI 42.8-80.2%) for positive results, 95.6% (95%CI 93.0-98.2%) for negative results and overall was 92.2% (95%CI 88.9-95.5%). CONCLUSIONS: (1) The discriminatory power of PCR and MSAO-direct is similar but the level of agreement, especially for true positive results, is low. (2) The potential TAT for the PCR method provides a marked advantage over conventional methods. (3) Further modifications to the PCR method such as increased broth incubation time, use of selective broth and adaptation to real-time PCR may lead to improvement in sensitivity and TAT.

Culture negative mitral valve endocarditis caused by Neisseria gonorrhoeae confirmed by 16S rDNA sequence analysis of resected valvular tissue.

Infective endocarditis is a dynamic disease with changing epidemiology and diagnostic strategies. Culture negative endocarditis poses a particular problem for clinicians regarding appropriate antimicrobial therapy and adequate duration of therapy. Utilization of nucleic acid amplification techniques and subsequent sequencing has provided clinicians an alternative to traditional phenotypic microbial identification which has been extremely useful in identification of fastidious organisms. We report a case of a young male with culture negative native mitral valve endocarditis and subsequent 16S rDNA sequencing of Neisseria gonorrhoeae from excised valvular tissue and embolic material. Identification of this organism with novel nucleic acid amplification and 16S rDNA sequence analysis techniques permitted targeted antibiotic therapy and successful treatment of this potentially fatal disease.

Nematode symbiont for Photorhabdus asymbiotica.

Photorhabdus asymbiotica is an emerging bacterial pathogen that causes locally invasive soft tissue and disseminated bacteremic infections in the United States and Australia. Although the source of infection was previously unknown, we report that the bacterium is found in a symbiotic association with an insect-pathogenic soil nematode of the genus Heterorhabditis.

Intraabdominal zygomycosis caused by Syncephalastrum racemosum infection successfully treated with partial surgical debridement and high-dose amphotericin B lipid complex.

Invasive zygomycosis rarely complicates trauma. We describe the first recorded case of invasive infection of the anterior abdominal wall and omentum with the zygomycete Syncephalastrum racemosum, which was successfully treated with partial surgical debridement and amphotericin B lipid complex.

9: Infections in the returned traveller.

The usual presentation of a returned traveller is with a particular syndrome - fever, respiratory infection, diarrhoea, eosinophilia, or skin or soft tissue infection - or for screening for asymptomatic infection. Fever in a returned traveller requires prompt investigation to prevent deaths from malaria; diagnosis of malaria may require up to three blood films over 36-48 hours. Diarrhoea is the most common health problem in travellers and is caused predominantly by bacteria; persistent diarrhoea is less likely to have an infectious cause, but its prognosis is usually good. While most travel-related infections present within six months of return, some important chronic infections may present months or years later (eg, strongyloidiasis, schistosomiasis). Travellers who have been bitten by an animal require evaluation for rabies prophylaxis.