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.

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 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.

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.

[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.

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.

Whole-cell protein profiles are useful for distinguishing enterococcal species recovered from clinical specimens.

Whole-cell protein analysis was performed for differentiating 150 enterococcal isolates to the species level, which had previously been identified by extended phenotypic conventional tests. Whole-cell protein profile (WCPP) showed a high degree of similarity within species and comparison between species revealed important differences in band profiles. All Enterococcus faecalis and Enterococcus faecium isolates were properly located into their corresponding species, regardless of their clinical source and susceptibility pattern. Moreover, WCPP allowed relocation of some isolates that had erroneously been identified by the usual conventional scheme (i.e. two atypical arginine-negative E. faecalis isolates). WCPP proved to be a simple method to ascertain the various enterococcal species, especially those other than E. faecalis, and may be a suitable tool for high-complexity or reference clinical laboratories.

Biofilm formation by Stenotrophomonas maltophilia isolates from device-associated nosocomial infections.

Medical devices are often colonized by bacteria which may cause severe infections. The aim of this work was to evaluate biofilm formation by S. maltophilia isolates from device-associated nosocomial infections. The 13 local isolates exhibited different capacities of biofilm formation on hydrophilic and hydrophobic surfaces. All isolates formed strong biofilms in polystyrene microplates, while strong, moderate or weak biofilms were detected in borosilicate (BS) or polypropylene (PP) tubes. The proficiency of biofilm formation was better evaluated by the level of crystal violet staining expressed relative to the final culture density. The microscopic analysis of biofilms formed on glass coverslips revealed the presence of a matrix of exopolysaccharides and microcolonies typical of biofilm architecture. Isolates with increased adhesion to BS showed larger microcolonies. According to our results, twitching correlated well with attachment to the three abiotic surfaces tested, while swimming only showed a slight correlation with biofilm formation on PP. Poor correlation was observed between cell surface hydrophobicity and biofilm formation. One of the highest biofilm-producing isolates adhered to urethral catheters of different materials, and exhibited an increased resistance to oxidative stress, one of the common stresses encountered by bacteria during the infection process due to the immune response.

[Investigation of Trichomonas vaginalis through different methodologies during pregnancy]. / Investigación de Trichomonas vaginalis durante el embarazo mediante diferentes metodologías.

The aim of this study was to conduct a survey regarding the prevalence of trichomoniasis in pregnant patients and to evaluate the utility of different diagnostic methods. Two hundred and twenty three vaginal swab specimens from pregnant women were prospectively examined. Trichomonas vaginalis was investigated by various microscopic examinations, solid culture medium and liquid culture medium. The sensitivity and specificity of microscopy were evaluated by considering both culture media as the "gold standards". The prevalence of T. vaginalis obtained by both culture media (liquid plus solid media) was 4.5% (10/223). The prevalence of T. vaginalis obtained by direct smear, May-Grunwald Giemsa staining, sodium acetate-acetic acid-formalin (SAF)/Methylene blue staining-fixing technique, solid medium and liquid medium was 1.3%, 1.8%, 1.8% and 4.5%, respectively. The sensitivity of the direct smear was 30 %, but for the May-Grunwald Giemsa staining and the SAF/Methylene blue staining-fixing technique was 40%. Considering the three microscopic examinations altogether, the sensitivity rose to 50% and the specificity was 100% for all of them. The solid medium detected only 50% of the positive cases; the liquid medium detected 100%. Due to the low sensitivity obtained with microscopy in asymptomatic pregnant patients, we recommend the use of the liquid medium during pregnancy, in order to provide an early treatment.

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.

[Prevalence of metallo-beta-lactamase in carbapenem resistant Pseudomonas aeruginosa at a university hospital of Buenos Aires City]. / Prevalencia de metalo-beta-lactamasas en pseudomonas aeruginosa resistentes a carbapenemes en un hospital universitario de Buenos Aires.

The present study was conducted to estimate the prevalence of metallo-beta-lactamases in 91 consecutive carbapenem resistant Pseudomonas aeruginosa isolates, recovered from inpatients at Hospital de Clínicas in Buenos Aires. Both, phenotypic and genotypic methods detected the presence of carbapenemases in 10 (11%) isolates, corresponding to VIM-11 in 7/10 and VIM-2 in the others. Codifying genes were all included in class 1 integrons, upstream genes coding for aminoglycoside modifying enzymes. One hundred percent sensitivity and specificity was achieved by the metallo-beta-lactamases phenotypic screening method using EDTA (1 micromol) disks in the Pseudomonas aeruginosa isolates included in this study. Sensitivity to aztreonam in carbapenem resistant isolates was suspicious of the presence of these enzymes.

[Evaluation of API Coryne System, version 2.0, for diphteroid gram-positive rods identification with clinical relevance]. / Evaluación del sistema API coryne, versión 2.0, para la identificación de bacilos gram-positivos difteroides de importancia clínica.

The ability of the API Coryne system, version 2.0, to identify 178 strains of gram-positive rods was evaluated. Seventy eight isolates belonged to genus Corynebacterium and one hundred to related genera, all strains were isolated from clinical samples at the Laboratory of Bacteriology, Hospital de Clínicas José de San Martin (UBA) between 1995 and 2004. The isolates were identified according to von Graevenitz and Funke's scheme. One hundred and sixty two out of 178 strains (91%) were correctly identified at genus and species level (IC95 = 85.6-94.6), in 44 of them (24.7%) additional tests were needed to final identification. Sixteen strains (9%) were not correctly identified (IC95 = 5.4-14.4); none of the 178 strains remained unidentified. The API Coryne system, version 2.0, is useful to identify the majority of Cory-nebacterium species with clinical relevance: Corynebacterium jeikeium, Corynebacterium urealyticum, Corynebacterium striatum, Corynebacterium pseudodiphtheriticum, Corynebacterium amycolatum and related species such as Arcanobacterium haemolyticum, Dermabacter hominis, Listeria monocytogenes, among others. Nevertheless for yellow-pigmented diphteroid gram-positive rods (Aureobacterium spp., Leifsonia aquatica, Microbacterium spp. and Cellulomonas spp.) and for acid fast gram-positive rods (Rhodococcus, Gordonia, Tsukamurella and Nocardia) the identification usefulness the system is limited.

[Comparison of different methods in order to identify Proteus spp]. / Comparación de diferentes métodos para identificar las especies del género Proteus.

Comparison of different methods in order to identify Proteus spp. The objectives were: (a) to identify Proteus strains to species level, following Farmer's and O'Hara's conventional biochemical reactions; b) to evaluate the sensitivity and specificity of both the API 20E method and a schema of reduced reactions (TSI and MIO agar: motility, indole and ornithine) comparing them with conventional methodology, and c) to evaluate the utility of SDS-PAGE (total proteins) in order to identify Proteus strains to species level. Two hundred and five Proteus spp. clinical isolates, were collected between January 1998 and September 2004, from inpatients and outpatients at Hospital de Clinicas. Strains were identified by means of conventional methodology, the API 20E method, and a schema of reduced reactions. SDS-PAGE (total proteins) was used in 48 out of the 205 strains. The API 20E method identified 79 out of 87 (90.8%) strains of P. mirabilis, 103 out of 103 P. vulgaris complex, and 15 out of 15 P. penneri. Eight strains of P. mirabilis were identified as Proteus spp., the acid production from maltose being necessary to identify them to species level. The schema of reduced reactions identified 205 out of 205 (100%) strains, that is, this schema of reduced reactions identified all the strains to species level without any additional tests, in marked contrast to the API 20E method. The SDS-PAGE (total proteins) identified the three species of the genus, even if the strains of P. mirabilis showed different biochemical reactions.

[Prevalence of vaginal candidiasis in pregnant women. Identification of yeasts and susceptibility to antifungal agents]. / Prevalencia de candidiasis vaginal en embarazadas. identificación de levaduras y sensibilidad a los antifúngicos.

Pregnant women are more susceptible to both vaginal colonization and infection by yeast. Our objectives were to determine the prevalence in pregnant women of yeasts isolated from vaginal exudates and their susceptibility to current antifungal drugs. A total of 493 patients was studied between December 1998 and February 2000. The prevalence of Candida spp. was 28% (Candida albicans 90.4%; Candida glabrata 6.3%; Candida parapsilosis 1.1%, Candida kefyr 1.1 %; unidentified species 1.1 %). The diffusion test in Shadomy agar was employed to determine the susceptibility to fluconazole, ketoconazole, itraconazole and nistatine. All C. albicans, C. kefyr and C. parapsilosis isolates were susceptible in vitro to the antifungal agents tested, while 1 in 6 C. glabrata isolates showed resistance to azole drugs; all strains were susceptible to nistatine. In pregnant women, C. albicans was the yeast most frequently isolated from vaginal exudates; it continues to be highly susceptible to antifungal drugs. Azole resistance was detected only among C. glabrata isolates. Identification to the species level is recommended, specially in cases of treatment failure and recurrent or chronic infection.