Hotspots sequences of gyrA, gyrB, parC, and parE genes encoded for fluoroquinolones resistance from local Salmonella Typhi strains in Jakarta.

BACKGROUND: Infection of Salmonella enterica subsp. enterica serovar Typhi is the primary etiology of typhoid fever globally and is common in many developing countries, especially those with dense populations and poor environmental sanitation. Antibiotic fluoroquinolones were used for the treatment in the 1980s due to the resistance to the first-line antibiotics. However, many cases of treatment failure of fluoroquinolones in typhoidal patients have been reported from numerous countries in Asia, Europe, Africa, and America. Mutations in quinolone resistance determining regions (QRDR) genes, gyrA, gyrB, parC, and parE, are found in fluoroquinolone-resistant Salmonella Typhi. Contrast reports came from the S. Typhi isolates in Indonesia, mainly Jakarta and the surroundings, obtained from patients with typhoid fever, with good sensitivity to the fluoroquinolones, i.e., nalidixic acid, ciprofloxacin, moxifloxacin, and levofloxacin. The present study, therefore, aimed to identify the hotspot sequences of gyrA, gyrB, parC, and parE genes of the local S. Typhi strains based on their susceptibility to fluoroquinolones from patients with typhoid fever in Jakarta and its satellite cities. RESULTS: A total of 28 isolates were identified as S. Typhi. All isolates were susceptible to nalidixic acid, levofloxacin, and moxifloxacin. Twenty-seven isolates (96.4%) were susceptible to ciprofloxacin, with one isolate (3.6%) being intermediate. The hotspot sequences of gyrA, gyrB, parC, and parE genes from all isolates were identical to the fluoroquinolone-sensitive reference sequence Salmonella enterica subsp. enterica serovar Typhi Ty2 (NCBI GenBank AE014613.1), including the isolate with intermediate susceptibility. The mutation was not found, and amino acid deduced from all hotspots in susceptible and intermediate isolates showed no replacement in all reported codons. CONCLUSIONS: This study showed that the local S. Typhi strains from Jakarta and surroundings were susceptible to fluoroquinolones (nalidixic acid, ciprofloxacin, levofloxacin, and moxifloxacin), and the hotspot sequences of the gyrA, gyrB, parC, and parE genes were all identical to the reference sequence. Thus, the hotspot sequences of the gyrA, gyrB, parC, and parE genes seemingly were conserved in Jakarta's local S. Typhi strains and could be considered wild type. The phenotypic susceptibility was consistent with the genotypic characteristic without non-synonymous mutations associated with drug resistance.

Severe α-thalassemia intermedia due to a compound heterozygosity for the highly unstable Hb Adana (HBA2: c.179G>A) and a novel codon 24 (HBA2: c.75T>A) mutation.

We report a novel mutation at codon 24 of the α2-globin gene (HBA2: c.75T > A) found in a Sundanese family. This novel mutation was detected during prenatal diagnosis. The couple already had a 7-year-old boy who exhibited clinically severe α-thalassemia intermedia (α-TI), and he was found to be a compound heterozygote for the novel mutation at codon 24 and the previously described Hb Adana (HBA2: c.179G > A) at codon 59 of the α2-globin gene. The father was a carrier of the novel point mutation and showed normal hemoglobin (Hb) and a low mean corpuscular volume (MCV) and mean corpuscular Hb (MCH) value.

Interaction of Hb adana (HBA2: c.179G>A) with deletional and nondeletional α(+)-thalassemia mutations: diverse hematological and clinical features.

We describe 27 cases of mild-to-severe α-thalassemia (α-thal) syndrome caused by interaction of Hb Adana [α59(E8)Gly→Asp, GGC>GAC (α2)] with deletional and nondeletional α(+)-thal mutations in Indonesian patients. Hematological profiles and clinical manifestations of all patients were assessed by routine procedures. The genotypes were generated by a multiplex-polymerase chain reaction (m-PCR), PCR-RFLP (restriction fragment length polymorphism)-based method, and DNA sequencing. The α-thal patients who had Hb Adana in combination with the 3.7 kb deletion mostly have mild-to-moderate anemia. In contrast, patients who were compound heterozygotes for Hb Adana and nondeletional mutations, generally showed a more severe anemia and it mostly presented in childhood. Thus, accurate diagnosis of α-thal disorders is not only important for future management of these patients but also for providing proper genetic counseling to the family.

Hydrops fetalis associated with homozygosity for Hb Adana [alpha59(E8)Gly-->Asp (alpha2)].

We describe cases of hydrops fetalis associated with nondeletional alpha-thalassemia (alpha-thal), in three unrelated Indonesian families. The genotypes of the fetuses and their parents were generated by DNA sequencing and by a polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP)-based method to rapidly identify mutations detected by sequencing. Two of the fetuses had hydrops fetalis and homozygous alpha59(E8)Gly-->Asp (alpha2), also known as Hb Adana. The third fetus was also suspected to be homozygous for Hb Adana because both parents were carriers of this mutation. This study shows that homozygosity for Hb Adana is associated with hydrops fetalis in the Indonesian population. We discuss this mutation and its various phenotypes including compound heterozygosity with other alpha-thal mutations and describe a simple approach to genetic testing that will clarify the risk of hydrops fetalis in the offspring of couples carrying this nondeletional mutation.