Selvaraj Stephen

As an obligate intracellular, Gram-negative microorganism, Chlamydia trachomatis represents a prevalent sexually transmitted pathogen. It disproportionately impacts women of reproductive age, resulting in a spectrum of reproductive health complications. Despite the significant public health implications of this infection, its epidemiological characteristics in India remain inadequately documented, with a limited number of studies conducted. Endocervical swabs and serum samples were collected from 75 participants. A solid-phase immunochromatographic assay was employed for the detection of antigens within the endocervical specimens. In accordance with the manufacturer’s protocols, an enzyme immunoassay was utilized to ascertain the presence of IgM, IgG, and IgA antibodies in the serum specimens. For the purposes of this investigation, we recruited 75 patients exhibiting various symptoms indicative of lower genital tract infections. Among the symptomatic cohort, thirteen cases tested positive for chlamydia antibodies. Notably, two of these thirteen patients exhibited the presence of both IgG and IgA antibodies. Chlamydia antibodies were identified in 17.3% (13/75) of the symptomatic patients, as determined by the results of the antibody detection assays. In relation to patients diagnosed with cervicitis, 61.5% tested positive and 19.4% tested negative for chlamydia antibodies (P value = 0.0040).

Background & objectives: Conventionally, the humoral immune response to scrub typhus (ST) is the early appearance of IgM during the first week of infection, followed by IgG after 2-3 weeks. Recent publications reveal different trends in Immunological response to ST. Methods: Acute and convalescent blood from 55 (Group-I) and single samples from 152 (Group-II), both clinically suspected as ST, were subjected to ST IgM ELISA, ST IgG ELISA, and ST IgG IFA. Acute samples from Group I and single samples from Group II were subjected to Real-Time PCR (q PCR) to target three genes, 56 kDa, 47 kDa, and groEl. Results: All 262 blood samples were positive for ST IgM ELISA. Positivity for IgG ELISA, IgG IFA and the presence of any one or more gene targets (56kDa/47kDa/groEL) in qPCR among the 55 acute samples was 70.9%, 36.4%, and 89.1%, respectively and 87.3%, 45.5% and 78.3% respectively in convalescent samples. In 152 unpaired samples, IgG ELISA was positive in 52.6% and 19.1% in ST IgG IFA. Among 207 samples (Group-I Acute and Group II) subjected to q PCR, groEl, 56 kDa and 47 kDa were present in 59.4%, 44.0%, and 35.7% respectively. Interpretation & conclusion: In view of the persistence of IgM in ST over months and, in some cases, years, there is a diagnostic dilemma in confirming ST based on single ST IgM, especially in ST-endemic regions. This is compounded by the additional presence of ST IgG in the early days of acute infection. q PCR is recommended to confirm doubtful cases of ST.

Enzyme linked Immunosorbent Assay (ELISA) and Immunofluorescence Assay (IFA) are specific serological tests for Scrub Typhus (ST). The etiological agent, Orientia tsutsugamushi DNA is demonstrable by PCR. Different countries apply ST IgM IFA cut-off titres ranging from 1:10 to 1:10240. To avoid confusion, Scrub Typhus Inclusion Criteria (STIC) was proposed. One criterion was a fourfold increase to or single IFA titre of ≥1:10240, later lowered to ≥1:3200. Equally sensitive and specific ELISA has no place in STIC. Modification of STIC is needed for robust laboratory confirmation of ST. One hundred and forty clinically suspected ST patients, including 58 patients who provided paired blood samples, were subjected to ST IgM ELISA, IgM IFA and Real time PCR targeting 56kDa, 47kDa and groEL genes. Among paired samples, all 58 (100%) acute sera were positive for IgM ELISA while 49 were positive in IgM IFA (84.5%). Among convalescent samples, 50 and 43 were positive in ST IgM ELISA and ST IgM IFA (86.2% and 74.1%) respectively. Regarding 82 unpaired samples, IgM ELISA and IgM IFA positivity was observed in 82 (100%) and 72 (87.8%) cases, respectively. PCR positivity in 140 ST cases for all three or any two gene targets, 56kDa, 46kDa and groEL as per STIC was 84, while an additional 40 samples were positive for any one gene. In Indian context, STIC requires modification to include IgM ELISA positivity, lower IgM cutoff IFA titre of ≥1:64 and any one gene positivity in Real time PCR.

The aim of this communication is to highlight the dangers of Q fever outbreaks in laboratories attempting isolation of Coxiella burnetii (C. burnetii) and other rickettsiae without Bio Safety Level (BSL)-3 facilities. This series is reported for the benefit of Microbiologists who evince interest in Rickettsial research. Four cases of Laboratory-acquired Q fever is presented among the laboratory personnel in a tertiary care teaching Hospital in Karnataka in 1977, which has not been reported yet. Four persons (one Lecturer, one animal technician and two M.Sc. students) who assisted in blood collection from slaughtered domestic livestock from butcheries and/or participated in the isolation of C. burnetii by guinea pig inoculation became seropositive for Q fever. The presence of antibodies to C. burnetii was demonstrated by two specific serological tests, Micro Agglutination Test (MAT) and Complement Fixation Test (CFT) for Q fever. They responded well to treatment with oxytetracycline, the drug of choice. It should be known that even microscopic demonstration of C. burnetii and other rickettsiae in the ectoparasites is hazardous, due to liberation of infective aerosol in the process. A safe commercial Q fever vaccine for laboratory and farm workers is presently available in Australia alone. Therefore, preventive measures like use of BSL-3 facility in the laboratory as well as animal house, wearing N95 face masks and protective clothing (PPE) are some of the essential precautions to follow so as to prevent laboratory acquired Q fever infection, which is an important occupational hazard.

Scrub typhus (ST) is a re-emerging zoonotic disease caused by Orientia tsutsugamushi and is transmitted by chiggers. Serological tests targeting IgM and/or IgG antibodies play a major role in the detection of ST cases. Orientia 56kDa genome is common target for the molecular diagosis of ST to identify the prevalence of specific serotypes of O. tsutsugamushi in and around Puducherry by targeting 56kDa gene with the application of phylogenetic analysis. This prospective laboratory-based study was conducted in a tertiary care teaching hospital, from November 2105 to March 2018. Blood samples were collected from out-patients/in-patients, and those tested positive for ST IgM ELISA (n=140) and an equal number of negative samples were archived and anonymized. Genomic DNA was extracted and analyzed by using Nested PCR and LAMP assay. The positive products were purified and sequenced. Phylogenetic tree was constructed based on the sequences. Among 280 samples, 45 (16.1%) N-PCR and 102 LAMP (36.43%) positivity was observed for 56kDa gene. Forty-one N-PCR positive products were sequenced and accession numbers were obtained (MG601875 to MG601917) for the isolates. Phylogenetic analysis was done by Maximum Likelihood methods and this study has showed that 32.3% are similar to the Karp isolates. Molecular diagnosis of Scrub typhus has become essential in case of doubtful serology and early acute phase of illness. Gene sequencing result indicates that most of them were different from the existing ones, which may belong to the newer strains. The identification of newer strains will be helpful in future for development of scrub typhus vaccine.

J Indian Prosthodont Soc, Official publication of Indian Prosthodontic Society

Background and Aim: Diagnosis of query fever (QF) is mostly done on the basis of serological/molecular tests, due to the stringent requirement of biosafety level-3 containment facilities for isolating Coxiella burnetii in culture. QF is an important zoonosis and is considered to be an occupational hazard to livestock handlers. This report describes our study on the serological as well as molecular evidence of QF in animal handlers from Puducherry and surrounding Tamil Nadu, from where, to the best of our knowledge, no such reports are available so far. Materials and Methods: Seventy-five animal handlers were recruited, comprising veterinarians, slaughterhouse workers, butchers, and animal attendants of various government veterinary clinics from Puducherry and surrounding areas of Tamil Nadu state. QF serology was performed to identify Phase I and Phase II immunoglobulin G antibodies to C. burnetii. Nested polymerase chain reaction (N-PCR) was carried out to detect C. burnetii DNA in buffy coat samples by targeting IS1111 gene element. N-PCR-positive samples were sequenced and phylogenetic analysis was performed using MEGA software version 10.0. Results: A total of 21 animal handlers (28.1%) were positive for either serology or PCR. PCR alone was positive in 10 (13.4%), only serology was positive in 8 (10.7%), and both serology and PCR were positive in three samples (4.0%). GenBank accession numbers were obtained for 13 N-PCR-positive samples (MG548608-MG548620). Six of our study sequences showed close similarity with the reference isolates from Bengaluru, Colombia, Brazil, France, and Iran. Conclusion: A significant percentage of QF positivity in animal handlers of this part of South India, Puducherry, warrants a prospective study with follow-up of a large number of this occupational group.