Microbiology of recurrent parotitis

Infantile chronic recurrent parotitis (ICRP) is characterized by episodes of recurrent swelling of the parotid gland with decreased salivary flow and purulent secretion. The etiology of this little unknown clinical condition has been attributed to multiple causes such as canalicular system malformations, ascending bacterial infection, hyposialia, parotitis sequelae, viral infections and immunologic disorders, among others.

We studied the types (with counts) of microorganisms involved in ICRP. Saliva samples were obtained from 56 patients and 20 controls, inoculated onto enriched media and incubated under aerobic and anaerobic conditions. Antimicrobial susceptibility and serotyping of the isolated organisms isolated were performed.

Of 57 saliva samples from ICRP patients, 52 (91%) were culture-positive. The most frequently isolated microorganisms were Streptococcus pneumoniae and Haemophilus influenzae. Thirteen of twenty (65%) samples were also culture-positive, mostly for viridans streptococci. However, colony counts were lower than in clinical samples (P < 0.004). Approximately one-third of S. pneumoniae strains resistant or moderately resistant to penicillin, and all H. influenzae strains were susceptible to all of the antimicrobials tested.

S. pneumoniae or H. influenzae were isolated in high concentrations in IRCP cases but not in controls, suggesting that these microorganisms may have a role in the development of this clinical entity. Quantitative cultures are very important in assessment of the pathogenic role of these microorganisms in patients but not in controls.