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Corynebacterium coyleae is part of the commensal microflora of the skin, urethra, mucous membranes, and genital tract. Isolates from patients with urinary tract infection (UTI) were reported, but the pathogenic potential of this species has not been defined yet. The aim of the study is to determine whether C. coyleae could be the etiological agent of UTI and to analyze its antibiotic susceptibility. Urine samples were cultured quantitatively according to accepted laboratory procedures. The identification of bacterial isolates was carried out using the Vitek MS (bioMérieux) and antibiotic susceptibility was tested using disc diffusion according to EUCAST guidelines. Between 1 January 2017 and 30 October 2018, a total of 39 C. coyleae strains were isolated. This represented 0.32% of all urine samples cultured in the laboratory during the collection period. The strains were isolated from samples obtained from 35 women and 3 men (age median for all-64 years). One female patient presented with C. coyleae in her urine twice at an interval of 21 months. In six cases of UTI, C. coyleae was isolated in monoculture. The isolates had the same resistance pattern. A total of 11 strains were obtained from cases with a clinical diagnosis of UTI. In 13 cases, the strain was cultured in a monoculture and in 28 cases with accompanying species. All strains were susceptible to vancomycin. However, resistance to ciprofloxacin was observed for 58.4% of the strains. Urine isolates of C. coyleae must be considered as contamination or normal flora in most cases (28/39, 72%). In the remaining cases, it can be considered as potential etiologic agents, mostly in women and especially in the 6 UTI cases where C. coyleae was found as the single culture-positive species. Several of these isolates demonstrate resistance to antibiotics commonly used in empiric treatment of urinary tract infections.

Corynebacterium urealyticum, formerly known as coryneform CDC group D2, was first recognized to be involved in human infections 30 years ago. It is a slow-growing, lipophilic, asaccharolytic and usually multidrug-resistant organism with potent urease activity. Its cell wall peptidoglycan, menaquinone, mycolic and cellular fatty acid composition is consistent with that of the genus Corynebacterium. DNA-DNA hybridization studies and 16S rDNA sequencing analysis have been used to determine the degree of relatedness of C. urealyticum to other corynebacterial species. The genome of the type strain consists of a circular chromosome with a size of 2 369 219 bp and a mean G + C content of 64.2%, and analysis of its genome explains the bacterium's lifestyle. C. urealyticum is a common skin colonizer of hospitalized elderly individuals who are receiving broad-spectrum antibiotics. It is an opportunistic pathogen causing mainly acute cystitis, pyelonephritis, encrusted cystitis, and encrusted pyelitis. More infrequently, it causes other infections, but mainly in patients with urological diseases. Infections are more common in males than in females, and treatment requires administration of antibiotics active against the organism in vitro, mainly glycopeptides, as well as surgical intervention, the latter mostly in cases of chronic infection. Mortality directly associated with infection by this organism is not frequent, but encrusted pyelitis in kidney-recipient patients may cause graft loss. The outcome of infection by this organism is reasonably good if the microbiological diagnosis is made and patients are treated appropriately.

Encrusted cystitis is a severe chronic inflammatory disease of the bladder characterized by excessively alkaline urine and calcifications within the bladder wall. A case of a 60 year-old man affected by systemic lupus erythematosus (SLE), which developed encrusted cystitis due to Corynebacterium urealyticum with E. coli co-infection, shows that the treatment of encrusted cystitis with a endoscopic debulking of the encrusted stones and an antimicrobial therapy specific for C. urealyticum often is not sufficient for the complete resolution of symptoms.

The incidence and characteristics of urinary tract infections caused by Corynebacterium urealyticum were studied prospectively in 20,766 urine samples. Corynebacterium urealyticum was isolated from 67 samples (0.32%). Twenty-four percent of the patients from whom Corynebacterium urealyticum was isolated showed mild symptoms and had no risk factors other than prolonged hospitalization and previous antibiotic treatment. Sixty percent of the patients had urinary tract-related symptoms. The main risk factors were underlying urinary tract disease, antibiotic treatment, prolonged hospitalization and urological manipulation. Patients with antimicrobial treatment had a favourable clinical course, with the exception of two patients with encrusted cystitis.

Corynebacterium urealyticum (formerly Corynebacterium group D2) has been implicated as a cause of alkaline-encrusted cystitis and urinary tract struvite calculi. Despite preselecting urine specimens with neutral and alkaline pHs and using prolonged incubation on a selective medium, isolation of this organism was rarely observed in a population of hospitalized patients. We do not recommend routine cultures for this organism unless the urine is alkaline and struvite crystals, leukocytes, and erythrocytes are present.

In the light of an informative clinical case report, the authors emphasise the pathogenic role of Corynebacteria D2 in urinary tract disease. This microorganism can be easily detected by bacteriologists by the use of special media and such infection is suggested clinically by urinary tract infection with "sterile", strongly alkaline urine. The clinical features of incrusted cystitis with alkaline urine may be accompanied by serious upper urinary tract complications with renal failure, recurrent haematuria with anaemia, decreased bladder capacity and incontinence. Corynebacteria D2, an opportunistic pathogenic bacteria, responsible for nosocomial infection, is resistant to the majority of antibiotics. The authors complete their case report with a review of the literature.

Forty urinary bladders were collected from apparently healthy cattle slaughtered at the Zaria abattoir. Twenty-four (60%) were from male animals and 16 (40%) from females. Urine samples were obtained and cultured for Corynebacterium renale. Four (16.7%) of the samples from males and 1 (6.3%) from females were positive. The difference in infection between the sexes was statistically significant (P less than 0.001).

Corynebacterium group D2 (CGD2) is a slow-growing, urea-splitting, multiantibiotic-resistant microorganism that is frequently isolated from urine samples and that, in certain circumstances, produces infection of the lower urinary tract (acute and chronic cystitis) and the upper urinary tract (pyelonephritis). This paper analyzes (by means of a retrospective and partially prospective clinical protocol) our experience with 82 patients with CGD2 bacteriuria. The infection was symptomatic in 62% of cases, and the clinical diagnoses included acute and chronic cystitis and pyelonephritis with or without bacteremia. Because CGD2 infection of the urinary tract may require specific antimicrobial treatment and because CGD2 is a fastidious microorganism, we recommend prolonged incubation of urine cultures (up to 48-72 hours), especially if the routine culture is negative, when patients are symptomatic, have alkaline urine, or have struvite crystals in the urine sediment.

Experimental and spontaneous infections with Corynebacterium suis in sows were investigated. In early stages animals show no clinical disorders or only for a short time. However, there are already marked changes in urinary samples (hematuria, proteinuria, leukocyturia, gross alterations). Using an endoscope mucosal irritations can be seen mainly on the floor of the bladders. In chronic cases alterations in urine are more pronounced. If a pyelonephritis is present in addition to the cystitis, general signs of illness are evident including anorexia, emaciation, anemia, subnormal body temperature and abortions. Bladders demonstrate an erosive and ulcerative, hemorrhagic cystitis on the whole mucosal surface. Uremia appears only in late stages of the disease.

The role of Corynebacterium renale urease in the establishment of pyelonephritis was studied by the oral administration of acetohydroxamic acid (AHA), a urease inhibitor, to experimentally infected rats. The bacteria were introduced by surgical insertion of a zinc disc containing 1 X 10(6) colony-forming units of C-renale into the urinary bladder whereas sterile discs were implanted in the bladders of the control animals. Daily administration of AHA via the drinking water did not halt the development of pyelonephritis. Larger doses, given by gavage, did accomplish this goal; that is, the pH of the urine was lowered, the number of colony-forming units of C. renale in the kidney was reduced drastically, and pyelonephritic lesions were observed in the kidney by light-microscopic examination. All experimental rats developed cystitis in varying degrees of severity. About 70% of the intact AHA given by gavage was excreted in the urine 24 h after administration of this compound. Rats implanted with a urease-negative mutant of C. renale displayed no signs of pyelonephritis but did develop cystitis.

One hundred and eight cattle (20 controls, 14 with an experimentally induced and 74 with spontaneously occurred suppurative surgery infection) were studied in terms of their general condition and some of the urine indices--pH, specific weight, proteins, urobillinogen, acetone, sugar, blood, urea and sediment. It was established that when the general status deteriorated and death occurred the urine pH value rose (by 1--1.5), and the specific weight was 0.005--0.010 higher, while the level of urina urea dropped by 0.5--0.6 g%. In 89 per cent of the investigated animals there were 0.1 per percent proteins, and the sediment consisted of 20--30 erythrocytes, from sporadic to 10-12 leucocytes, and from single to 5--6 kidney epithelium cells per field. In 38.8 per cent of the cattle affected with suppurative processes there were tripelphosphates in the sediment. Urobillinogen was found in 63.6 per cent of the cases. Suppurative infections caused by Corynebacterium pyogenes are accompanied by greater changes in the sediment. In almost all of the recovered animals the urine indices came back to normal.

Corynebacterium group D2 inoculated into normal human urine formed struvite crystals and an increase in pH and ammonium concentration after 24 h of incubation. Zinc disks dipped into a broth culture of this microorganism and inserted into the bladders of rats produced stones with a mean weight of 12.5 mg (ranging from 1 to 57.7 mg) after 12 days. Analysis of the infrared spectrum determined the stones to be composed of struvite. From these results its seems that stone formation by Corynebacterium group D2 may be possible both in vitro and in vivo, which may confirm a previous report involving these bacteria in human clinical encrusted cystitis.