Haemophilus parahaemolyticus

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Haemophilus parahaemolyticus
Kingdom:
Phylum:	Pseudomonadota
Class:	Gammaproteobacteria
Order:	Pasteurellales
Family:	Pasteurellaceae

Haemophilus parahaemolyticus is a species of bacteria in the genus Haemophilus, which is part of the family Pasteurellaceae. This bacterium is a Gram-negative, facultatively anaerobic organism that is part of the normal flora of the human upper respiratory tract.

Morphology

Haemophilus parahaemolyticus is a small, non-motile, pleomorphic Gram-negative coccobacillus. It does not form spores and is typically 0.3 to 1.0 micrometers in diameter. The bacterium has a characteristic "school of fish" appearance when observed under a microscope due to its tendency to form chains.

Growth and Metabolism

Haemophilus parahaemolyticus requires specific growth factors for cultivation, namely NAD (nicotinamide adenine dinucleotide), also known as V factor. It does not require hemin (X factor) for growth, which differentiates it from other species such as Haemophilus influenzae. The bacterium grows best at 35-37°C in a carbon dioxide-enriched atmosphere.

Pathogenicity

While Haemophilus parahaemolyticus is generally considered non-pathogenic, it can occasionally be associated with opportunistic infections, particularly in individuals with compromised immune systems. It is not typically associated with invasive disease but may be isolated from respiratory tract infections.

Clinical Significance

Haemophilus parahaemolyticus is part of the normal flora of the human nasopharynx and is usually non-pathogenic. However, in rare cases, it can be involved in respiratory tract infections, particularly in patients with underlying conditions such as chronic obstructive pulmonary disease (COPD) or cystic fibrosis.

Laboratory Identification

The identification of Haemophilus parahaemolyticus in the laboratory involves culturing the organism on media supplemented with V factor, such as chocolate agar. The bacterium can be differentiated from other Haemophilus species by its requirement for V factor only and its inability to grow on media lacking this factor.

Treatment

Infections caused by Haemophilus parahaemolyticus are typically treated with antibiotics. The organism is generally susceptible to a range of antibiotics, including amoxicillin, cephalosporins, and macrolides. However, antibiotic susceptibility testing is recommended to guide therapy.

Prevention

Since Haemophilus parahaemolyticus is part of the normal flora, specific preventive measures are not typically necessary. General measures to maintain a healthy immune system and avoid respiratory infections are recommended.

See Also

• Haemophilus
• Pasteurellaceae
• Respiratory tract infections

External Links

• [Link to relevant microbiology resources]