Lactobacillus rhamnosus hepatic abscess associated with Mirizzi syndrome: a case report and review of the literature

The clinical significance of Lactobacillus spp. isolated from clinical specimens has often been overlooked due to its low virulence. We report the first case of life-threatening bacteremic liver abscess due to Lactobacillus rhamnosus associated with Mirizzi syndrome in a 74-year-old Chinese man. Literature on sporadic reports of Lactobacillus liver abscess is reviewed.     

KRAS and PIK3CA but not BRAF genes are frequently mutated in Chinese cholangiocarcinoma patients

Cholangiocarcinoma (CCA) is a rare but lethal malignancy arising from the biliary tract epithelium. It has a poor prognosis largely due to the difficulties of early diagnosis and the lack of effective therapies. It is thus imperative to develop new and effective treatments for CCA, which depends heavily on the mechanistic understanding of the disease. Previous studies have suggested that somatic mutations in KRAS, BRAF, and PIK3CA genes are frequently found in several types of human cancers including colon, breast, and lung carcinomas as well as CCA. Yet, the frequency and the involvement of these oncogenic mutations in CCA in Chinese population have not been investigated. In this study, we evaluated the hotspot mutations of KRAS, BRAF, and PIK3CA genes in 34 Chinese CCA patients. Sequencing analysis revealed 13 (38.2%) and 11 (32.4%) patients bearing KRAS and PIK3CA mutations, in which two (5.9%) of them harbored both KRAS and PIK3CA mutations. Surprisingly, no BRAF mutation was detected in all 34 CCA samples. Our findings indicate that somatic mutations in KRAS and PIK3CA but not BRAF oncogenes are closely associated with the development of CCA in Chinese population and provide new potential targets for future therapeutic treatments of the disease.     

A case of catheter-related bloodstream infection caused by Mycobacterium phocaicum

We present a patient with double hit Burkitt's like lymphoma who developed a catheter-related bloodstream infection due to Mycobacterium phocaicum that was identified by rpoB gene sequencing. His infection resolved with 7 weeks of antibiotics and port-a-cath removal.     

Orbital cellulitis and endogenous endophthalmitis secondary to Proteus mirabilis cholecystitis

We report the first case of orbital cellulitis and endogenous endophthalmitis secondary to Proteus mirabilis bacteremia that resulted from a calculus cholecystitis. Despite resolution of the gallbladder infection with antimicrobial therapy, the patient required evisceration of the affected eye. The pathogenesis of hematogenous endophthalmitis due to Gram-negative bacilli is discussed.     

Primary peritonitis due to Streptococcus pyogenes with reduced susceptibility to fluoroquinolones

We report the 1st case of primary peritonitis caused by Streptococcus pyogenes with a reduced susceptibility to fluoroquinolones in a healthy woman, leading to a clinical and microbiological treatment failure. DNA sequencing of parC and gyrA revealed the association of the following 3 substitutions in ParC: Ser80Pro, Asp91Asn, and Ser140Pro.     

Cross-recognition of aspergillus galactomannan caused by Listeria monocytogenes infection

We report a case of Listeria monocytogenes bacteremia in a leukemic patient having a positive assay for aspergillus galactomannan (GM), although no evidence of aspergillosis was found. Supernatant obtained from L. monocytogenes strain suspension was reactive with GM-assay. L. monocytogenes produces a soluble antigen that is cross-reactive with Aspergillus GM.     

Prospective evaluation of virulence factors of enterococci isolated from patients with peritonitis: impact on outcome

The objective of this study was to evaluate the prevalence of 4 virulence factors (VFs) of enterococci (cytolysin [cyl], gelatinase [gel], aggregation substance [agg], and enterococcal surface protein [esp]) and their relationship to outcome in patients with generalized peritonitis in a prospective cohort study. VF expression in each strain was assessed by polymerase chain reaction assay with specific primers. Outcome of the patients was recorded. Ninety-nine strains of Enterococcus were obtained from the peritoneal fluid of 81 patients. Fifty-eight patients had at least 1 strain bearing [cyl] (13.1% of the strains), [gel] (50.5% of the strains), [agg] (40.4% of the strains), and [esp] (34.3% of the strains). The presence of VF of Enterococcus was independently associated with mortality: odds ratio, 5.5; 95% confidence interval, 1.3-28.1. In conclusion, VF accounted for 72% of the patients with enterococci isolated from the peritoneal fluid and was independently associated with mortality in severe peritonitis.     

Rapid detection of coinfections by Trichomonas vaginalis, Mycoplasma hominis, and Ureaplasma urealyticum by a new multiplex polymerase chain reaction

We developed a multiplex polymerase chain reaction (M-PCR) assay to simultaneously detect Trichomonas vaginalis, Mycoplasma hominis, and Ureaplasma urealyticum. The test is extremely specific and has a sensitivity of 10 cells for T. vaginalis and U. urealyticum and of 1 cell for M. hominis. The technique was validated on vaginal swabs from 240 women presenting symptoms of vaginitis, and results were compared with data obtained using microscopic and culture techniques on the same patients. The M-PCR revealed to be greatly more sensitive and specific than traditional techniques. It has been well demonstrated, in vitro, that T. vaginalis can establish a symbiosis with M. hominis; our data confirm in vivo this strict association: in fact, M. hominis has been detected in 78.6% of all samples positive for T. vaginalis, as compared to only 4.8% of women without trichomoniasis. The species specificity of this association has been confirmed by the absence of any significant correlation between T. vaginalis and U. urealyticum.     

Risk factors for mortality in patients with bloodstream infections caused by carbapenem-resistant Pseudomonas aeruginosa: clinical impact of bacterial virulence and strains on outcome

The incidence of carbapenem-resistant Pseudomonas aeruginosa (CRPA) bacteremia has increased in recent years, and infections caused by CRPA result in higher mortality than those caused by susceptible strains. This study was performed to evaluate the risk factors for mortality and to study the impact of virulence factors and bacterial strains on clinical outcomes in patients with CRPA bacteremia. Data on 63 episodes of CRPA bacteremia that have occurred between January 1, 2007, and December 31, 2009, in a teaching hospital (2000 beds) in Seoul, Korea, were analyzed. The Acute Physiology and Chronic Health Evaluation II (APACHE II) score at the time of CRPA bacteremia and the capacity of CRPA to form biofilm were independent predictive factors for mortality in patients with CRPA bacteremia. In addition, the biofilm-forming ability and elastase activity of strains were correlated with APACHE II scores to measure the severity of disease and estimate predicted mortality in the patients.     

Co-colonization of vanA and vanB Enterococcus faecium of clonal complex 17 in a patient with bacteremia due to vanA E. faecium

A 53-year-old Vietnamese man with liver cirrhosis was transferred from a Vietnamese hospital to our tertiary care hospital in Korea in order to undergo a liver transplantation. Bacteremia due to vanA Enterococcus faecium was diagnosed, and stool surveillance cultures for vancomycin-resistant enterococci (VRE) were positive for both vanA and vanB E. faecium. Pulsed-field gel electrophoresis analysis revealed that the 2 vanA VRE isolates from the blood and stool were clonal, but the vanB VRE was unrelated to the vanA VRE. vanA and vanB VRE were ST64 and ST18, single-allele variations of clonal complex 17, respectively. This is the first case report of vanA VRE bacteremia in a Vietnamese patient and demonstrates the reemergence of vanB VRE since a single outbreak occurred 15 years ago in Korea. The reemergence of vanB VRE emphasizes the importance of VRE genotyping to prevent the spread of new VRE strains.     

Morbidity associated with Pseudomonas aeruginosa bloodstream infections

We sought to quantify patient morbidity throughout Pseudomonas aeruginosa bloodstream infection (PABSI) as a function of patient covariates. Individuals with PABSI were included in a retrospective, observational, cohort study. Morbidity was quantified by serial Sequential Organ Failure Assessment (SOFA) scores. Impact of active antimicrobial treatment was assessed as a function of changes in SOFA scores as the dependent variable. A total of 95 patients with PABSI were analyzed. Relative to baseline SOFA scores (day −2), scores after PABSI were increased by 37% on day 0 and 22% on day +2 but returned to baseline on day +7. Overall mortality was 37%, and mean length of hospital stay (postculture) was 16 days. Most patients were appropriately treated, with n = 83 (87%) receiving an active agent and n = 61 (64%) receiving >1 agent. As a result, an effect of therapy on morbidity was not observed. Advanced age and elevated baseline SOFA scores predicted increased in-hospital mortality (P = 0.01 and P < 0.001, respectively) and morbidity at day +2 (P < 0.05 and P < 0.05, respectively) and day +7 (P < 0.05 and P < 0.001, respectively). Neutropenia was also associated with increased morbidity at day +2 (P < 0.05). In treated PABSI, morbidity is highest the day of the diagnostic blood cultures and slowly returns to baseline over the subsequent 7 days. Age and baseline severity of illness are the strongest predictors of morbidity and mortality. Because neither of these factors are modifiable, efforts to minimize the negative impact of PABSI should focus on appropriate prevention and infection control efforts.     

Muscular abscess caused by Cupriavidus gilardii in a renal transplant recipient

Cupriavidus gilardii is a rare cause of human infection. We report a muscular abscess on the right thigh caused by this organism in a renal transplant recipient, who had suffered a septic shock associated with an extensive cellulitis caused by Streptococcus pyogenes. The patient was successfully treated with surgical drainage and intravenous ciprofloxacin for 13 days. This is the first time that C. gilardii is isolated from a human abscess. C. gilardii should be considered as a cause of human infection, especially in immunocompromised patients. Infection caused by this organism may be underdiagnosed because the identification is very difficult.     

Decreased quinolone susceptibility in high percentage of Enterobacter cloacae clinical isolates caused only by Qnr determinants

The prevalence of qnr genes was similar in the ciprofloxacin-resistant and ciprofloxacin-susceptible Enterobacter cloacae isolates, and no amino acid change in quinolone resistance-determining regions was found in any of the 21 qnr-positive but ciprofloxacin-susceptible strains. Qnr may thus be present before the development of higher-level resistance from target mutations.     

A case of osteitis due to Staphylococcus aureus and Arcanobacterium bernardiae coinfection

Arcanobacterium bernardiae human infections remain rare. Only 2 reports are described in the literature. We report on an immunocompetent patient with a long history of chronic osteitis who developed a polymicrobial infection of the knee. The initial isolation of Staphylococcus aureus confounded the diagnosis of A. bernardiae infection, which underlines the need for extended period of incubation and subcultures of enriched liquid culture media. A. bernardiae is a new bacterium implicated in osteoarticular infections.     

Microbiology of peritonitis in peritoneal dialysis patients with multiple episodes

♦ Background: Peritoneal dialysis (PD)–associated peritonitis clusters within patients. Patient factors contribute to peritonitis risk, but there is also entrapment of organisms within the biofilm that forms on PD catheters. It is hypothesized that this biofilm may prevent complete eradication of organisms, predisposing to multiple infections with the same organism.♦ Methods: Using data collected in the Canadian multicenter Baxter POET (Peritonitis, Organism, Exit sites, Tunnel infections) database from 1996 to 2005, we studied incident PD patients with 2 or more peritonitis episodes. We determined the proportion of patients with 2 or more episodes caused by the same organism. In addition, using a multivariate logistic regression model, we tested whether prior peritonitis with a given organism predicted the occurrence of a subsequent episode with the same organism.♦ Results: During their time on PD, 558 patients experienced 2 or more peritonitis episodes. Of those 558 patients, 181 (32%) had at least 2 episodes with the same organism. The organism most commonly causing repeat infection was coagulase-negative Staphylococcus (CNS), accounting for 65.7% of cases. Compared with peritonitis caused by other organisms, a first CNS peritonitis episode was associated with an increased risk of subsequent CNS peritonitis within 1 year (odds ratio: 2.1; 95% confidence interval: 1.5 to 2.8; p < 0.001). Among patients with repeat CNS peritonitis, 48% of repeat episodes occurred within 6 months of the earlier episode.♦ Conclusions: In contrast to previous data, we did not find a high proportion of patients with multiple peritonitis episodes caused by the same organism. Coagulase-negative Staphylococcus was the organism most likely to cause peritonitis more than once in a given patient, and a prior CNS peritonitis was associated with an increased risk of CNS peritonitis within the subsequent year.     

Predictive genetic risk markers for strong biofilm-forming Staphylococcus aureus: fnbB gene and SCCmec type III

To find predictive genetic risk markers for strong biofilm producers of Staphylococcus aureus, we studied the relatedness of agr and SCCmec types and fnbB and IS256 genes to biofilm-forming ability in 465 clinical isolates. fnbB and SCCmec type III are candidates as genetic risk predictors for the strong biofilm producers.     

Acinetobacter pittii and Acinetobacter nosocomialis among clinical isolates of the Acinetobacter calcoaceticus-baumannii complex in Sichuan,China

Among 82 clinical isolates of the Acinetobacter calcoaceticus-baumannii complex recovered in 13 hospitals of Sichuan, China, in 2011, 13 were Acinetobacter pittii and 2 were Acinetobacter nosocomialis. Multilocus sequence typing revealed a novel sequence type (ST) of A. nosocomialis and 7 novel STs of A. pittii. Most isolates were hospital-acquired and colonized in the respiratory tract, while 6 cases with pneumonia due to A. pittii were identified. This study provided a snapshot of the local incidence of A. pittii and A. nosocomialis.     

Rapid identification of Salmonella enterica subsp. arizonae and S. enterica subsp. diarizonae by real-time polymerase chain reaction

Reptiles are popular as pets, leading to an increased risk of human infections due to uncommon Salmonella strains including the Arizona group (subspecies arizonae and diarizonae). We present a real-time Arizona-specific polymerase chain reaction demonstrating 100% specificity and 99.6% sensitivity, offering savings in time and labor over traditional identification methods.     

Microbiological investigation and clinical significance of Corynebacterium spp. in respiratory specimens

The purpose of this retrospective study was to evaluate the pathogenic role of Corynebacterium species in lower respiratory tract infections as well as their routine laboratory investigation. From April 2007 to August 2009, 27 clinical isolates were significantly recovered from respiratory specimens of 27 different patients clinically suspected of having lower respiratory tract infections. The average age of patients was 65 years, while 22 (81%) patients presented at least 1 predisposing condition. Of the 27 patients, 15 (56%) were classified as infected according to Centers for Disease Control and Prevention/National Healthcare Safety Network criteria, with 93% of infections being hospital acquired. All isolates were accurately identified to the species level using molecular methods (i.e., 17 Corynebacterium pseudodiphtheriticum, 7 Corynebacterium striatum, and 3 Corynebacterium accolens), whereas phenotypic methods remained frequently unreliable for identifying C. striatum and C. accolens strains. All tested isolates were susceptible to amoxicillin, imipenem, vancomycin, linezolid, and tigecycline, whereas most of them were resistant to erythromycin.     

First case report of sepsis caused by Mycobacterium wolinskyi in chronic myelogenous leukemia

Infections caused by Mycobacterium wolinskyi have rarely been reported, and essentially all were cellulitis and/or osteomyelitis related with traumatic event or surgical wound. Here, we present the 1st case of septic complication due to this organism in a patient with chronic myelogenous leukemia of the 1st but late chronic phase.