Characterization of coagulase-negative staphylococci from urinary tract specimens

Abstract

Species of coagulase-negative staphylococci isolated from urine specimens submitted from both inpatients and outpatients to the clinical microbiology laboratory of a teaching hospital were identified with a biotyping system, with species then correlated by clinical features and antimicrobial susceptibility. Of 145 isolates, 102 (70%) were Staphylococcus epidermidis, 24 (17%) were Staphylococcus saprophyticus, 7 (4.7%) were Staphylococcus haemolyticus, 4 (2.8%) were Staphylococcus hominis, 3 (2.1%) were Staphylococcus simulans, and 5 (3.4%) were other species. Features characterizing persons with bacteriuria with S. saprophyticus compared with bacteriuria with any other species included female sex (95% versus 52%), young age (median age, 22 years versus 61 years), ambulatory status (hospital outpatients, 86% versus 23%), and absence of indwelling catheters (4.5% versus 49%). All other coagulase-negative staphylococci were isolated in a setting suggesting nosocomial acquisition, were more frequently resistant to common antimicrobial agents (42% multiply resistant versus 4.2% of S. saprophyticus), and were not distinguished by clinical features. Novobiocin susceptibility, with a sensitivity of 100o and specificity of 96%, provided a simple and reliable test for differentiation of S. saprophyticus from other coagulase-negative staphylococci and should be routinely used for urinary tract specimens in the clinical laboratory.

Identification, clinical distribution, and susceptibility to methicillin and 18 additional antibiotics of clinical Staphylococcus isolates: nationwide investigation in Italy

“…The predominance of lyogroup V (S. epidermidis) in strains from blood and cerebrospinal fluid may be related to the special ability of this species to infect indwelling artificial devices (5, 7) and to cause bacteremias in compromised patients (36). The higher overall antibiotic sensitivity of lyogroups III and IV is in agreement with that which has been reported in other studies for S. capitis (10,35) and S. saprophyticus (18,19), respectively. The almost constant susceptibility to vancomycin exhibited by all lyogroups is consistent with the excellent in vitro antistaphylococcal activity of this drug emphasized in recent reports (3,5,19,30).…”

“…Significant species-to-species differences have emerged which concern both the clinical distribution and antimicrobial susceptibility of the isolates. The greater incidence of lyogroup IV in strains from outpatients with respect to that in strains isolated from inpatients and the predominance of this lyogroup among isolates from urine and urethral specimens are consistent with the well-documented importance of novobiocin-resistant staphylococci (especially S. saprophyticus) in acute cystitis in young female outpatients (4,11,15,17,18,37) and in other urological infections with complications, including urethritis (9) and pyelonephritis (8,29). The predominance of lyogroup V (S. epidermidis) in strains from blood and cerebrospinal fluid may be related to the special ability of this species to infect indwelling artificial devices (5, 7) and to cause bacteremias in compromised patients (36).…”

Quantitative urine cultures do not reliably detect renal candidiasis in rabbits

“…As a standard of care, leading textbooks of infectious diseases, nephrology, and clinical microbiology cite the importance of 10 5 CFU/ml as a critical breakpoint for significant bacteriuria (14,34,36), and algorithms in the classic texts suggest that workup for urethritis be pursued when members of the family Enterobacteriaceae are detected at concentrations below this. Such breakpoints, however, may have limited validity for different patient populations or organisms other than the Enterobacteriaceae (21,25), organisms vastly different from Candida in their size, biology, virulence, and pathogenicity. Furthermore, clinical laboratories process urine specimens and report results in a standard fashion, and these CFU/milliliter thresholds are therefore extrapolated to candiduria.…”

Cell-surface hydrophobicity ofStaphylococcus saprophyticus

“…All strains of S. saprophyticus were isolated from urine specimens, from symptomatic female patients, submitted to a large private pathology laboratory serving the general community. All catalase-positive, coagulase-negative, Grampositive cocci were initially screened for novobiocin (5 ,ug disk) susceptibility [15] and later identified using the classification scheme of Kloos and Schleifer [16], as incorporated in the API STAPH micromethod.…”