Hemolytic Haemophilus are rarely isolated in the clinical laboratory, as they do not grow on sheep or human blood-agar alone. On rabbit blood-agar they grow well and are hemolytic, but they grow less well and are not hemolytic on sheep blood-agar with added X and V factors. A survey was made to determine their incidence in pharyngitis. From 28 of 100 sore throats and from 57 of 100 normal throats, only normal bacterial flora were isolated. beta-Streptococci were present in significant numbers in 9 sore and 11 normal throats; staphylococci in 8 sore and 4 normal throats; pneumococci in 20 sore and 11 normal throats; H. influenzae or H. parainfluenzae in 13 sore and no normal throats; hemolytic Haemophilus in 30 sore and 18 normal throats; enteric bacilli in 1 of each; Candida and Neisseria in 2 sore throats each. All of the 33 hemolytic Haemophilus isolates identified to species were H. parahaemolyticus. All were sensitive in vitro to chloramphenicol, erythromycin, and tetracycline; 30 were sensitive to ampicillin and 30 to penicillin, 26 to novobiocin, and 12 to methicillin. H. influenzae, H. parainfluenzae, and H. haemolyticus are indistinguishable by Gram stain morphology, but H. parahaemolyticus is larger than the other three. Hemolytic and nonhemolytic species are indistinguishable by colonial morphology or by nutritional requirements; only hemolysis gives positive differentiation. Nevertheless, only rarely would this be of clinical importance. H. parahaemolyticus apparently may cause pharyngitis, but it is almost always susceptible to penicillin and rarely if ever causes sequelae.

Anti-Bacterial Agents↗

PubMed1968

Identification of Micrococcaceae in clinical bacteriology.

The cellular morphology, identifying physiological characteristics, and a key to the human genera of Micrococcaceae are presented with flow charts for identification of aerobic and anaerobic isolates. These flow charts can be amended as desired, depending upon the degree of accuracy desired. Micrococcaceae isolates in a 350-bed private general hospital during a 15-week period are tabulated to show relative numbers of the different genera and species, with their probable relationship to infection or contamination. Only 11 of the 220 Micrococcaceae isolates were not Staphylococcus; no Sarcina or Peptococcus were isolated. Of the Staphylococcus isolates, 61% were S. epidermidis. Almost 18% of the S. aureus isolates were coagulase-negative. Of the S. aureus isolates, 80% of the coagulase-positive isolates were infecting agents, as were 67% of the coagulase-negative S. aureus isolates, compared to only 48% of S. epidermidis isolates. Two of four Gaffkya isolates but only one of seven Micrococcus isolates were infecting agents. If coagulase production is used as the sole criterion for speciation of staphylococci, and Micrococcus is not differentiated from Staphylococcus, the term "coagulase-negative staphylococci" does not differentiate three distinct levels of pathogenicity. Coagulase-negative S. aureus is more virulent than S. epidermidis or Gaffkya, which are more virulent than Micrococcus or Sarcina.

Bacteriological Techniques↗

PubMed1968