Clinical Profile of Patients and Antifungal Susceptibility Pattern of Invasive Cryptococcus neoformans Isolates from Pakistan

Abstract

Background: Cryptococcosis affects immunocompromised as well as immunocompetent individuals. A wide spread improper
antifungal use has resulted in antifungal resistance. Data regarding clinical characteristics and antifungal susceptibilities of Cryptococcus neoformans from Pakistan is limited.

Objective: To determine clinical characteristics of patients and antifungal resistance in invasive Cryptococcus neoformansisolates.

Method: This study was conducted at Aga Khan University Hospital, Karachi, Pakistan from 2009-2016. Forty-nine Cryptococcus
neoformans strains were isolated from various clinical specimens. Clinical data for inpatients was collected through medical
records and for outpatients, it was collected by interviews via phone calls to patients or attendants. Antifungal susceptibilities
were evaluated for amphotericin B, flucytosine and fluconazole by broth microdilution (BMD).

Results: Cryptococcosis was seen in immunosuppressed states and in conjunction with chronic infections like hepatitis B (n=2), hepatitis C (n=2) and tuberculosis (n=3). Outcomes were not known for 67% (n=37) of patients. Incidence was higher in adult patients 82% (n=40), and 67% (n=37) cases occurred in males. For all isolates, MIC50 and MIC90 were within the epidemiological cut off values (ECVs) for 5-flucytosine and fluconazole. One isolate had MIChigher than ECV for amphotericin B.

Conclusion: Invasive cryptococcal infections are seen in immunocompromised population as well as in association with certain risk factors such as chronic infections, diabetes and steroid use. Thorough evaluation of all patients must be done for risk factors to ensure better clinical outcomes. Since antifungal resistance is on the rise globally and our findings also show isolated amphotericin B resistance, it is important to perform susceptibility testing of all clinical strains to optimize therapy and for continuous surveillance.

Key words: Cryptococcosis, Cryptococcus neoformans, Antifungal susceptibilities