High frequency of multiresistant respiratory tract pathogens at community level in South India

ObjectiveTo describe the patterns of antibiotic susceptibility of outpatient strains of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis in the district of Pondicherry in South India.MethodsThe antibiotic susceptibilities of 94 S. pneumoniae, 97 H. influenzae and 104 M. catarrhalis strains, collected from outpatients with respiratory tract infections, were determined by disk diffusion and Etest.ResultsResistance or reduced susceptibility to trimethoprim–sulfamethoxazole was found in 67% of S. pneumoniae, 53% of H. influenzae and 24% of M. catarrhalis strains. Thirty-seven per cent of S. pneumoniae and 39% of H. influenzae strains were resistant or showed reduced susceptibility to tetracycline. Reduced susceptibility to penicillin was found in 6% of S. pneumoniae strains. Overall, 10% of S. pneumoniae and 38% of H. influenzae strains showed reduced susceptibility to ≥3 antibiotics. Comparisons between the antibiotic susceptibility patterns of the Indian strains and a corresponding collection of strains from Sweden indicate that the susceptibility of the native susceptible population is independent of geographic origin.ConclusionsThe findings indicate high consumption of tetracycline and trimethoprim–sulfamethoxazole in the area, which emphasizes the need for surveillance of the pattern of antibiotic susceptibility among respiratory tract pathogens at community level in developing countries and for the implementation of local guidelines for rational use of antibiotics

Use of a T cell interferon gamma release assay in the investigation for suspected active tuberculosis in a low prevalence area

<p>Abstract</p> <p>Background</p> <p>In settings with low background prevalence of tuberculosis (TB) infection, interferon-γ release assays (IGRA) could be useful for diagnosing active TB. This study aims to evaluate the performance of QuantiFERON^®-TB Gold (QFT-G) in the investigation for suspected active TB, with particular attention to patients originating in high-incidence countries. Furthermore, factors associated with QFT-G results in patients with active TB were assessed.</p> <p>Methods</p> <p>From patients investigated for clinically suspected active TB, blood was obtained for QFT-G testing, in addition to routine investigations. Positive (PPV) and negative (NPV) predictive values for QFT-G were calculated, comparing patients with confirmed TB and those with other final diagnoses. QFT-G results in TB patients originating from countries with intermediate or high TB incidence were compared with QFT-G results from a control group of recently arrived asymptomatic immigrants from high-incidence countries. Factors associated with QFT-G outcome in patients with confirmed TB were assessed.</p> <p>Results</p> <p>Among 141 patients, 41/70 (58.6%) with confirmed TB had a positive QFT-G test, compared to 16/71 (22.6%) patients with other final diagnoses, resulting in overall PPV of 71.9% and NPV of 67.6%. For patients with pulmonary disease, PPV and NPV were 61.1% and 67.7%, respectively, and 90.5% and 66.7% for subjects with extrapulmonary manifestations. Comparing patients from high-incidence countries with controls yielded a PPV for active TB of 76.7%, and a NPV of 82.7%. Patients with confirmed TB and positive QFT-G results were characterized by a lower median peripheral white blood cell count (5.9 × 10⁹/L vs. 8.8 × 10⁹/L; <it>P </it>< 0.001) and a higher median body mass index (22.7 vs. 20.7; <it>P </it>= 0.043) as compared to QFT-G-negative TB patients.</p> <p>Conclusion</p> <p>The overall PPV and NPV of QFT-G for identifying active TB were unsatisfactory, especially for pulmonary disease. Thus, the usefulness of QFT-G for this purpose is questionable. However, a high PPV was observed for extrapulmonary TB and QFT-G might be considered in the diagnostic process in this situation. The PPV and NPV for identifying active TB among persons originating from regions with high-and intermediate TB incidence was similar to that observed in subjects originating in the low-incidence region.</p

30 år av framgångsrik mykobakterieforskning. AHRI i Addis Abeba ­ unik forskningsmiljö i u-land

The Armauer Hansen Research Institute (AHRI) in Addis Abeba, Ethiopia, was established by the Swedish and Norwegian Save the Children organisations in collaboration with the University of Bergen, with the principal objective of pursuing basic research in leprosy. The institute has a commendable record of achievement, and has made significant contributions to our understanding of leprosy and its control, and to the training of scientists from Ethiopia and other African countries. Recently, the Ethiopian, Swedish and Norwegian governments agreed to continue supporting the AHRI as an autonomous research centre. Its main objectives will be to conduct research in mycobacterial diseases, particularly tuberculosis, and to promote the enhancement of human resources in health research through instruction, supervision, and scientific collaboration

Improved isolation of mycobacteria other than Mycobacterium tuberculosis on isoniazid-containing Lowenstein-Jensen medium

The benefit of including isoniazid-containing Lowenstein-Jensen medium for primary isolation of mycobacteria was evaluated in 3,726 clinical specimens. This media increased the primary isolation of mycobacteria other than Mycobacterium tuberculosis by 9.2%, facilitated macroscopical reading and aided presumptive identification of the isolated mycobacteria

Assay of type-specific M antigens on whole group A streptococci

A novel radioimmunoassay of type-specific M antigens on whole group A streptococcal cells is described. Absorbed rabbit anti-M antisera directed against M types 12 and 49 were used for determining M antigens on intact bacterial organisms. Staphylococcal protein A labelled with 125I was used as an anti-antibody reagent. The absorbed antisera were tested against ten homologous and 48 heterologous serotypes. All homologous serotypes gave an unequivocal reaction distinct from the weaker reaction with the heterologous serotypes. The type-specificity of the reaction was confirmed by the removal of type-specific antibodies after absorption to purified M protein coupled to Sepharose 4B. The results indicate that the described method is a simple and reliable technique for the recognition of M types of group A streptococci and offers a valuable tool for studies of M antigen in situ

Species-specific identification of methicillin resistance in staphylococci

The ability to identify methicillin-resistant staphylococci by the disc diffusion method was evaluated using discs containing oxacillin (1, 5 and 10 micrograms), methicillin (10 micrograms) and cephalexin (30 micrograms). Strains of Staphylococcus aureus (67 strains) and coagulase-negative staphylococci (72 novobiocin-sensitive and 27 novobiocin-resistant strains) were studied using two inoculum densities (10(6) cfu/ml and 10(8) cfu/ml). Inhibitory zones were recorded after 18, 24 and 42 hours of incubation. A mecA-specific application of the polymerase chain reaction was used as a reference method. The inoculum of 10(8) cfu/ml and incubation for 24 hours were optimal for the identification of methicillin-resistant strains. However, one single disc was not sufficient for the identification of methicillin resistance in the different staphylococcal species. The mecA-positive strains of Staphylococcus aureus and novobiocin-resistant coagulase-negative species were clearly separated from the mecA-negative strains when the 5 micrograms oxacillin disc was used, whereas the 1 microgram oxacillin disc was optimal for the identification of the mecA-positive novobiocin-sensitive coagulase-negative strains

Comparison of strand displacement and ligase chain amplification for detection of Chlamydia trachomatis infection in urogenital specimens.

ABSTRACTTwo amplification tests for the diagnosis of Chlamydia trachomatis infection, namely the ligase chain reaction (LCx) and the strand displacement assay (ProbeTec), were compared using samples from 1183 patients at sexually transmitted disease clinics. The overall prevalence of positive results was 8.0%, with agreement between the two assays of 98.8%. For endocervical, urethral and male urine samples, agreement was 99.3%, 99.4% and 97.7%, respectively. For ten discrepant samples, alternative amplification assays suggested that the LCx and ProbeTec assays gave erroneous results in six and four cases, respectively. Inhibition of amplification was observed with three (0.25%) urine specimens