Manual of Clinical Microbiology


Aerococcus, Abiotrophia, and Other Aerobic Catalase‐Negative, Gram‐Positive Cocci

Last Updated:2023

The catalase‐negative, Gram‐positive cocci included in this chapter form a taxonomically diverse group of bacteria that are isolated infrequently as opportunistic agents of infection. Most of these organisms resemble other,…

Description of the Genera

The organisms included in this chapter form Gram‐positive coccoid cells, but G. haemolysans may appear Gram variable or Gram negative due to the ease with which its cells are decolorized…

Epidemiology and Transmission

The organisms discussed in this chapter are opportunistic pathogens. Some of the genera have been characterized as constituents of the normal microbiota of the human oral cavity or upper respiratory…

Clinical Significance

The bacteria described in this chapter may be present as contaminants in clinical cultures, but they are also isolated infrequently as opportunistic pathogens. Blood, cerebrospinal fluid, urine, and wound specimens…

Collection, Transport, and Storage of Specimens

No special requirements for collection and transport of specimens for isolation of the organisms discussed in this chapter have been described. Routine procedures for collection, transport, and storage of specimens…

Direct Examination

The organisms described in this chapter can be visualized in direct Gram stains of clinical material but have no outstanding morphological characteristics that distinguish them from commonly isolated Gram‐positive cocci…

Isolation Procedures

Generally, there are no special requirements for isolation of the group of bacteria discussed here; general recommendations for the culture of blood, body fluids, and other specimens should be followed…


While molecular characterization may be required for accurate species‐level identification of the aerobic catalase‐negative, Gram‐positive cocci encountered infrequently in clinical laboratories, phenotypic methods can be helpful in characterization of ...

Typing Systems

Little information exists on typing methods for the genera of infrequently isolated Gram‐positive cocci included in this chapter. Typing is not routinely used for characterizing these organisms. If needed, typing…

Serologic Tests

The serologic response to the organisms described in this chapter has not been extensively investigated. No clinically useful tests have been described…

Antimicrobial Susceptibilities

Antimicrobial susceptibility studies on the organisms mentioned in this chapter have generally employed dilution testing methods. Few or no data exist on the utility of disk diffusion or the correlation…

Evaluation, Interpretation, and Reporting of Results

Efforts to identify the Gram‐positive cocci included in this chapter should be made only when isolates are considered clinically significant (i.e., isolated repeatedly, in pure culture, or from normally sterile…

Section Editor: Christine Y. Turenne

Volume Editor: Alexander McAdam

Editors in Chief: Karen C. Carroll and Michael A. Pfaller

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