Urinary tract infections caused by anaerobic bacteria. Utility of anaerobic urine culture.

Urinary tract infections (UTIs) caused by anaerobic bacteria have scarcely been reported. Since anaerobic bacteria are commensals of the genitourinary tract, their presence in a urine sample adds ambiguity in making a definitive diagnosis of anaerobic UTI. It is well known that standard urine culture is the gold standard method for the detection, identification, and antimicrobial susceptibility testing of uropathogens. Nonetheless, both the difficulties in establishing them as pathogens and the scarcity of reported anaerobic UTI cases led to the discontinuation of routine urine culture under an anaerobic atmosphere (UCAA). On the other hand, it is important to emphasize that culture-independent methods, such as proteomics and molecular technics, may detect anaerobes directly on a urine sample. Anaerobes are not included in guidelines for the diagnosis and management of UTIs. At the same time, as fastidious uropathogens and antibiotic resistance become more common, accurate pathogen identification becomes even more important for effective UTI treatment. As a result, we conducted a review of the clinical context, pathogen antimicrobial susceptibility, and treatment of patients with anaerobic UTIs. Because UCAA is a contentious topic, we narrowed our search to cases with both negative standard urine culture and positive UCAA.

Peptostreptococcus anaerobius: Pathogenicity, identification, and antimicrobial susceptibility. Review of monobacterial infections and addition of a case of urinary tract infection directly identified from a urine sample by MALDI-TOF MS.

Peptostreptococcus anaerobius is a gram-positive anaerobic coccus (GPAC) found in the gastrointestinal and vaginal microbiota. The organism is mainly found in polymicrobial and scarcely in monobacterial infections such as prosthetic and native endocarditis. Anaerobic bacteria have rarely been reported as the cause of urinary tract infection (UTI). Although GPAC are susceptible to most antimicrobials used against anaerobic infections, P. anaerobius has shown to be more resistant. Herein, we report a case of UTI caused by P. anaerobius from a 62-year-old man with a history of urological disease. Surprisingly, the microorganism was directly identified by Matrix-Assisted Laser Desorption-Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) from the urine sample. The isolate was successfully identified by phenotypic methods, MALDI-TOF MS, and 16S rRNA gene sequencing. P. anaerobius showed no ß-lactamase-producing activity, was resistant to penicillin, ampicillin, ciprofloxacin and levofloxacin, and displayed intermediate susceptibility to ampicillin-sulbactam and amoxicillin-clavulanic acid. Successful treatment was achieved with oral amoxicillin-clavulanic acid. Antimicrobial susceptibility testing (AST) should be performed on P. anaerobius isolates due to their unpredictable AST patterns and because empirically administered antimicrobial agents may not be active. This report shows that MALDI-TOF MS, directly used in urine specimens, may be a quick option to diagnose UTI caused by P. anaerobius or other anaerobic bacteria. This review is a compilation of monobacterial infections caused by P. anaerobius published in the literature, their pathogenicity, identification, and data about the antimicrobial susceptibility of P. anaerobius.

Clostridium ramosum rapidly identified by MALDI-TOF MS. A rare gram-variable agent of bacteraemia.

Clostridium ramosum is an enteric anaerobic, endospore-forming, gram-positive rod with a low GC content that is rarely associated with disease in humans. We present a case of C. ramosum bacteraemia. To the best of our knowledge, this is the second case of C. ramosum bacteraemia in an elderly patient presenting with fever, abdominal pain and bilious emesis. We highlight the Gram stain variability, the lack of visualization of spores and the atypical morphology of the colonies that showed C. ramosum in a polymicrobial presentation that initially appeared to show monomicrobial bacteraemia. The microorganism was rapidly identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). We present a comprehensive literature review of 32 cases of clinical infections by C. ramosum in which we describe, if available, sex, age, clinical symptoms, predisposing conditions, other organisms present in the blood culture, other samples with C. ramosum , identification methodology, treatment and outcome.

Intra-peritoneal abscess after an abdominal hysterectomy involving Cutibacterium avidum (former Propionibacterium avidum) highly resistant to clindamycin.

Cutibacterium avidum is a gram-positive anaerobic rod belonging to the cutaneous group of human bacteria with preferential colonization of sweat glands in moist areas. The microorganism rarely cause disease, generally delayed prosthetic joint infections (PJIs). We describe the second case of intraperitoneal abscess by C. avidum after an abdominal surgery in an obese female patient and the first case after a non-prosthetic abdominal surgery due to a highly clindamycin resistant strain in a patient with underling conditions. The patient was successfully treated with surgical drainage and beta-lactam antibiotics. Although rare and apparently non-pathogenic, C. avidum may be involved in infections, especially in some high-risk patients with obesity who have undergone surgical incision involving deep folder of the skin. The microorganism was identified by phenotypic methods, MALDI-TOF MS and 16S rRNA gene sequencing. Susceptibility test should be performed in C. avidum because high level resistance to clindamycin could be present. We present a literature review of C. avidum infections.

First report of Comamonas kerstersii causing urinary tract infection.

The association of Comamonas kerstersii with peritonitis resulting from perforated appendix and its isolation from a psoas abscess and pelvic peritonitis have previously been described by us. We present the first case of C. kerstersii urinary tract infection, broadening the spectrum of infections caused by this species.

First case of bacteraemia due to Acinetobacter schindleri harbouring blaNDM-1 in an immunocompromised patient.

Clinically significant NDM-1-producing Acinetobacter schindleri has not yet been described in the literature. We report the first case of bacteraemia due to an A. schindleri strain harbouring blaNDM-1 recovered from an immunocompromised patient. Our report reinforces the fact that NDM-1 can easily be acquired by Acinetobacter species.

Unusual presentations of Comamonas kerstersii infection.

The association of Comamonas kerstersii with peritonitis resulting from the presence of perforated appendix has previously been described by our research team. In the present study, we describe the isolation of this microorganism from two forms of unusual presentations of C. kerstersii infection not previously described in the literature: localized intra-abdominal infection (psoas abscess) and pelvic peritonitis.

Brote de Ralstonia mannitolilytica a partir de bacteriemias asociadas a catéteres implantables y semiimplantables en un hospital pediátrico / Outbreak of Raistonia mannitolilytica by implantable and semi-implantable catheter-related bacteremia in a pediatric hospital

Ralstonia mannitolilytica junto con Ralstonia pickettii han sido asociadas con brotes hospitalarios relacionados con la contaminación de algún dispositivo o fluido. El objetivo de este trabajo fue describir un brote por R. mannitolilytica a partir de bacteriemias asociadas a catéteres implantables y semiimplantables ocurrido en un hospital pediátrico de alta complejidad y evaluar la utilidad del empleo de métodos moleculares para su investigación.Se detectó la presencia de bacilos gram negativos no fermentadores, con igual antibiotipo, en hemocultivos y retrocultivos a partir de dos pacientes que tenían catéteres implantables y estaban atendidos en una misma área del hospital. Se realizaron estudios microbiológicos de muestras de frascos de heparina, soluciones de dextrosa y soluciones antisépticas con resultado negativo. Algunos pacientes tuvieron signos y/o síntomas clínicos de bacteriemia al habilitar los catéteres para su uso. Se citaron para su estudio a todos los pacientes que habían tenido un procedimiento de apertura y cierre de catéter durante las fechas cercanas a los hallazgos en hemocultivos (N expuestos = 45). Ocurrieron 17 casos (infectados), a partir de los cuales se analizaron 23 aislamientos, en los que se pudo documentar la presencia de R. mannitolilytica (23 aislamientos). Por métodos moleculares se determinó que los aislamientos provenientes de muestras de pacientes involucrados en el brote se encontraban estrechamente relacionados y podrían representar una misma cepa o clon. Por evidencia circunstancial se consideró a la "solución heparínica de cierre" como fuente posible del brote (AU)

Both Ralstonia mannitolilytica and Ralstonia pickettii have been associated with hospital outbreaks due to device or fluid contamination. The aim of this study was to describe an implantable- or semi-implantable-catheter-related bacteremia outbreak by R. mannitolilytica in a tertiary-care hospital and to assess the usefulness of molecular analysis for the identification of the organism. Non-fermenting gram-negative bacilli, with identical antibiotypes, were detected in hemocultures of two patients with implantable catheters in the same hospital area. Microbiological studies of heparin and dextrose and antiseptic solution vials were negative. Some of the patients had clinical signs and/or symptoms of bacteremia when the catheter was prepared for use. All patients who underwent a procedure of accessing or locking the port of the catheter around the time of the positive hemoculture findings were contacted (N exposed = 45). Seventeen infections were detected, of which 23 isolates were analyzed. The presence of R. mannitolilytica was recorded in 23 isolates. Molecular analysis showed that the isolates from the samples of the patients involved in the outbreak were closely related and might represent the same strain or clone. Circumstantial evidence suggested that the heparin-lock solution may have been the source of the outbreak (AU)

Context-dependent adaption of EpCAM expression in early systemic esophageal cancer.

The role of the epithelial cell adhesion molecule EpCAM in cancer progression remains largely unclear. High expression of EpCAM in primary tumors is often associated with more aggressive phenotypes and EpCAM is the prime epithelial antigen in use to isolate circulating tumor cells (CTCs) and characterize disseminated tumor cells (DTCs). However, reduced expression of EpCAM was associated with epithelial-to-mesenchymal transition (EMT) and reports on a lack of EpCAM on CTCs emerged. These contradictory observations might reflect a context-dependent adaption of EpCAM expression during metastatic progression. To test this, EpCAM expression was monitored in esophageal cancer at different sites of early systemic disease. Although most of the primary esophageal tumors expressed high levels of EpCAM, the majority of DTCs in bone marrow lacked EpCAM. In vitro, downregulation of EpCAM expression at the plasma membrane was observed in migrating and invading cells, and was associated with a partial loss of the epithelial phenotype and with significantly decreased proliferation. Accordingly, induction of EMT through the action of TGFß resulted in substantial loss of EpCAM cell surface expression on esophageal cancer cells. Knock-down or natural loss of EpCAM recapitulated these effects as it reduced proliferation while enhancing migration and invasion of cancer cells. Importantly, expression of EpCAM on DTCs was significantly associated with the occurrence of lymph node metastases and with significantly decreased overall survival of esophageal cancer patients. We validated this observation by showing that high expression of EpCAM promoted tumor outgrowth after xenotransplantation of esophageal carcinoma cells. The present data disclose a dynamic expression of EpCAM throughout tumor progression, where EpCAM(high) phenotypes correlate with proliferative stages, whereas EpCAM(low/negative) phenotypes associated with migration, invasion and dissemination. Thus, differing expression levels of EpCAM must be taken into consideration for therapeutic approaches and during clinical retrieval of disseminated tumor cells.

First case of Streptococcus lutetiensis bacteremia involving a clindamycin-resistant isolate carrying the lnuB gene.

Here, we describe the first case of a Streptococcus lutetiensis isolate harboring the lnuB gene.

Evaluation of the Andromas matrix-assisted laser desorption ionization-time of flight mass spectrometry system for identification of aerobically growing Gram-positive bacilli.

Matrix-associated laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is a rapid and simple microbial identification method. Previous reports using the Biotyper system suggested that this technique requires a preliminary extraction step to identify Gram-positive rods (GPRs), a technical issue that may limit the routine use of this technique to identify pathogenic GPRs in the clinical setting. We tested the accuracy of the MALDI-TOF MS Andromas strategy to identify a set of 659 GPR isolates representing 16 bacterial genera and 72 species by the direct colony method. This bacterial collection included 40 C. diphtheriae, 13 C. pseudotuberculosis, 19 C. ulcerans, and 270 other Corynebacterium isolates, 32 L. monocytogenes and 24 other Listeria isolates, 46 Nocardia, 75 Actinomyces, 18 Actinobaculum, 11 Propionibacterium acnes, 18 Propionibacterium avidum, 30 Lactobacillus, 21 Bacillus, 2 Rhodococcus equi, 2 Erysipelothrix rhusiopathiae, and 38 other GPR isolates, all identified by reference techniques. Totals of 98.5% and 1.2% of non-Listeria GPR isolates were identified to the species or genus level, respectively. Except for L. grayi isolates that were identified to the species level, all other Listeria isolates were identified to the genus level because of highly similar spectra. These data demonstrate that rapid identification of pathogenic GPRs can be obtained without an extraction step by MALDI-TOF mass spectrometry.

[Staphylococcus aureus: new and old antimicrobial agents]. / Staphylococcus aureus: nuevos y antiguos antimicrobianos.

The objective of the study was to evaluate the susceptibility to old and new antimicrobial agents against hospital-acquired oxacillin-resistant Staphylococcus aureus (HA-ORSA), community-acquired oxacillin-resistant S. aureus (CA-ORSA), and oxacillin-susceptible S. aureus(OSSA). The minimum inhibitory concentration of different antimicrobial agents against 118 S. aureus consecutive and prospective isolates was studied by the CLSI agar dilution method. In ORSA isolates without accompanying resistance, the mecA gene, the Panton-Valentine leukocidin gene (PVL), and the gamma-hemolysin gene were determined by PCR, and the SCC cassette mec gene by multiplex PCR. Out of the 118 isolates, 44 were HA-ORSA, 16 were CA-ORSA, and 58 corresponded to OSSA. The HA-ORSA isolates presented simultaneous resistance to erythromycin, clindamycin, gentamicin, ciprofloxacin, levofloxacin, and moxifloxacin whereas all of them were susceptible to tigecycline (TIG), vancomycin, teicoplanin and linezolid (LZD). The CA-ORSA isolates were only resistant to OXA and presented susceptibility to all the antimicrobial agents assayed. In all of them, the mec-A gene, the PVL gene, the gamma-hemolysin gene and the SCC cassette mec type IV gene were detected. With the OSSA and CA-ORSA isolates, all the non-beta-lactam antimicrobial agents assayed exhibited excellent in vitro activity. However, in the HA-ORSA isolates, only the old antimicrobial agents such as glycopeptides, doxyciclin, rifampin, and trimethoprim-sulfamethoxazole and the new antimicrobial agents LZD and TIG, presented good in vitro activity. The ORSA phenotype without accompanying resistance was highly predictive of CA-ORSA as confirmed by a positive SCC cassette mec type IV.

[Microbiological and epidemiological evaluation of carbapenem-resistant Acinetobacter baumannii clones isolated at an intensive care unit of a University Hospital in Buenos Aires city]. / Evaluación microbiol6gica y epidemiológica de los clones de Acinetobacter baumannii resistentes a los carbapenemes aislados en la unidad de cuidados intensivos de un Hospital Universitario de la ciudad de Buenos Aires.

From June to December 2004, thirty-three carbapenem-resistant Acinetobacter baumannii isolates recovered from twenty nine patients at the intensive care unit in Hospital de Clínicas, Universidad de Buenos Aires, were studied. The isolates were categorized by molecular methods as: clone I (n = 14), clone IV (n = 7), clone III (n = 6), clone VI (n = 3), clone II (n = 2) and clone X (n = 1). Twenty one isolates were recovered from lower respiratory tract samples, 11 of which belonged to clone I. Clone III isolates were mainly recovered from non-respiratory samples (5/6). Clone IV isolates were recovered from patients not receiving previous imipenem therapy. The majority of the isolates belonging to clones I and IV were able to survive on inert materials for more than 5 days, whereas adhesion to catheters was observed in isolates belonging to clones I and III, especially in those related to bacteremia. Clone III isolates showed colistin, gentamicin and levofloxacin susceptibility, whereas clone I isolates and most from clone IV were only susceptible to colistin and tetracyclines.

Evaluación microbiológica y epidemiológica de los clones de Acinetobacter baumannii resistentes a los carbapenemes aislados en la unidad de cuidados intensivos de un Hospital Universitario de la ciudad de Buenos Aires / Microbiological and epidemiological evaluation of carbapenem-resistant Acinetobacter baumannii clones isolated at an intensive care unit of a University Hospital in Buenos Aires city

Entre junio y diciembre de 2004 se estudiaron 33 aislamientos de Acinetobacter baumannii resistentes a los carbapenemes, aislados de materiales clínicos de 29 pacientes internados en la unidad de cuidados intensivos del Hospital de Clínicas de la Universidad de Buenos Aires. La distribución clonal de esos aislamientos fue la siguiente: clon I (n = 14), clon IV (n = 7), clon III (n = 6), clon VI (n = 3), clon II (n = 2) y clon X (n = 1).Veintiún aislamientos se recuperaron de materiales del tracto respiratorio inferior, 11 de ellos pertenecieron al clon I. Casi todos los aislamientos pertenecientes al clon III (5/6) se recuperaron de materiales no respiratorios, y todos los del clon IV se recuperaron de pacientes que no recibieron imipenem. En los aislamientos pertenecientes a los clones I y III se observó una mayor adherencia a catéteres, principalmente en los asociados con bacteriemias. La mayoría de los aislamientos de los clones I y IV sobrevivieron en materiales inertes durante un período superior a los 5 días. La totalidad de los aislamientos del clon III fueron sensibles a colistina, gentamicina y levofloxacina, mientras que los del clon I y la mayoría de los del clon IV sólo fueron sensibles a colistina y tetraciclinas.

From June to December 2004, thirty-three carbapenem-resistant Acinetobacter baumannii isolates recovered from twenty nine patients at the intensive care unit in Hospital de Clínicas, Universidad de Buenos Aires, were studied. The isolates were categorized by molecular methods as: clone I (n = 14), clon IV (n = 7), clone III (n = 6), clone VI (n = 3), clone II (n = 2) and clone X (n = 1). Twenty one isolates were recovered from lower respiratory tract samples, 11 of which belonged to clon I. Clone III isolates were mainly recovered from non-respiratory samples (5/6). Clone IV isolates were recovered from patients not receiving previous imipenem therapy. The majority of the isolates belonging to clones I and IV were able to survive on inert materials for more than 5 days, whereas adhesion to catheters was observed in isolates belonging to clones I and III, especially in those related to bacteremia. Clone III isolates showed colistin, gentamicin and levofloxacin susceptibility, whereas clone I isolates and most from clone IV were only susceptible to colistin and tetracyclines.