<prompt> A single, 30-year-old woman presents to her physician with vaginitis. She complains of a slightly increased, malodorous discharge that is gray-white in color, thin, and homogenous. Clue cells are discovered when the discharge is examined microscopically. Which of the following organisms is the most likely cause of her infection?Candida albicansTrichomonas vaginalisEscherichia coliGardnerella vaginalis  <response>: Microscopic examination can readily demonstrate clue cells epithelial cells with Gardnerella bacteria attached or pseudohyphae Candida. A wet mount will be needed to demonstrate motile Trichomonas cells. Candida, Trichomonas, and bacterial vaginitis are seen most often. Staphylococcus aureus is involved much less frequently. While E. coli may be a common cause of genitourinary infection, clue cells are usually absent. See the below table for a comparison of these bacteria.GRAM-NEGATIVE RODS ASSOCIATED WITH THE RESPIRATORYTRACTSpeciesMajor DiseasesLaboratory DiagnosisFactors X and V Required for Vaccine GrowthVaccine availableProphylaxis for ContactsHaemophilusinfluenzaeMeningitisa; otitis media, sinusitis, pneumonia, epiglottitisCulture; capsular polysaccharide in serum or spinal fluidRifampinBordetelhpertussisWhooping cough pertussisFluorescent antibody on secretions; culture-ErythromycinLegionellapneumophilaPneumoniaSerology; urinary antigen; culture--None aIn countries where the H. influenzae b conjugate vaccine has been deployed, the vaccine has greatly reduced the incidence of meningitis caused by this organism.CLINICAL FEATURES OFVAGINITIS NormalVulvovaginal Candidiasis TrichomoniasisBacterial VaginosisSymptomsNonePruritus SorenessSoreness DyspareuniaOften asymptomatic Occasional abdominal pain DyspareuniaOften asymptomatic DischargeAmountVariableScantmoderateProfuseModerateColorClearwhiteWhiteGreen-yellowWhitegrayConsistencyNonhomogeneous floccularClumped, adherentHomogeneous, frothyHomogeneous adherentVaginal Fluid pH4.0-4.54.0-4.55.0-6.04.5Amine test fish odorNoneNoneUsually positivePositiveMicroscopySalinePMN:EC ratio 1 Lactobacilli predominatePMN:EC1Pseudohyphae 40PMN:EC1Motile trichomonads PMNs predominatePMN:EC1Clue cells Coccobacilli10 KOHNegativePseudohyphae 70NegativeNegativePMN, polymorphonuclear leukocytes; EC, epithelial cells. 