Dihydropteroate synthase (DHPS) gene mutation study in HIV-Infected Indian patients with Pneumocystis jirovecii pneumonia.
BACKGROUND
Pneumocystis jirovecii dihydropteroate synthase (DHPS) gene mutations' (55th and 57th codon) association with prior sulfa prophylaxis failure has been reported from both developed and developing countries. We conducted a prospective study to determine the prevalence of P. jirovecii DHPS mutations from 2006 to 2009 on P. jirovecii isolates obtained from HIV-infected patients with a clinical diagnosis of Pneumocystis carinii pneumonia (PCP) admitted to our tertiary care reference health center in New Delhi, India.


METHODS
Detection of P. jirovecii cysts was performed by direct fluorescent antibody (DFA) staining and by Grocott's-Gomori methenamine silver staining (GMS). DNA detection was performed by polymerase chain reaction (PCR) using primers for the major surface glycoprotein (MSG) gene. P. jirovecii DHPS gene was amplified by nested PCR protocol and sequenced for detecting mutations at the 55th and 57th codons.


RESULTS
Out of 147 HIV-positive patients with suspected Pneumocystis pneumonia (PCP), 16 (10.8%) PCP positive cases were detected. Of 16 cases, nine (56.2%) were positive by DFA staining, four (25%) were positive by Grocott's-Gomori methenamine silver staining, and all 16 were positive by MSG PCR. DHPS mutations at the 55th and 57th codons were observed in 6.2% of HIV patients studied, which was relatively low compared to reports from developed nations.


CONCLUSIONS
Prevalence of Pneumocystis jirovecii DHPS mutations associated with cotrimoxazole treatment failure may be low in the Indian subpopulation of HIV-positive patients and warrants larger studies to elucidate the true picture of Pneumocystis jirovecii sulfa drug resistance in India.
All India Institute of Medical Sciences (AIIMS), New Delhi, India.
Anuj Kumar
AK
Tyagi
Bijay Ranjan
BR
Mirdha
Kalpana
K
Luthra
Randeep
R
Guleria
Anant
A
Mohan
Urvashi Balbir
UB
Singh
Jyotish Chandra
JC
Samantaray
Lalit
L
Dar
Venkateswaran K
VK
Iyer
Rama
R
Chaudhry
D017088:AIDS-Related Opportunistic Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D000293:Adolescent; D000328:Adult; D000890:Anti-Infective Agents / Q000494:pharmacology / Q000627:therapeutic use; D004094:Dihydropteroate Synthase / Q000235:genetics*; D025141:Drug Resistance, Fungal; D005260:Female; D015658:HIV Infections / Q000150:complications*; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D045363:Pneumocystis carinii / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D011020:Pneumonia, Pneumocystis / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D016133:Polymerase Chain Reaction; D015995:Prevalence; D011446:Prospective Studies; D016896:Treatment Outcome; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000494:pharmacology / Q000627:therapeutic use; D055815:Young Adult
D000890:Anti-Infective Agents; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D004094:Dihydropteroate Synthase