Kn Brahmadathan

INCIDENCE OF CARBAPENEM RESISTANT NONFERMENTING GRAM NEGATIVE BACILLI FROM PATIENTS WITH RESPIRATORY INFECTIONS IN THE INTENSIVE CARE UNITS

Resistance to carbapenems is commonly seen in nonfermenting gram negative bacilli (NFGNB). We document herein the prevalence of carbapenem resistance in NFGNB isolated from patients with respiratory tract infections in the intensive care units (ICUs). A total of 460 NFGNB were isolated from 606 endotracheal aspirate specimens during January through December 2003, of which 56 (12.2%) were found to be resistant to imipenem and meropenem. Of these, 24 (42.8%) were Pseudomonas aeruginosa , 8 (14.2%) were Acinetobacter spp. and 24 (42.8%) were other NFGNB. Stringent protocols such as antibiotic policies and resistance surveillance programs are mandatory to curb these bacteria in ICU settings

Nasopharyngeal colonization of infants in southern India with Streptococcus pneumoniae.

To investigate the dynamics of nasopharyngeal colonization with Streptococcus pneumoniae, and to determine the prevalent serogroups/types (SGT) and their antimicrobial susceptibility, we studied 100 infants attending our well-baby clinic. Nasopharyngeal swab specimens were obtained at 6, 10, 14, 18 and 22 weeks and at 9 and 18 months of age and submitted for culture, serotyping and antimicrobial susceptibility testing of S. pneumoniae. Colonization with pneumococcus was seen on at least one occasion in 81 infants. The median age of acquisition was 11 weeks and the median duration of carriage was 1 3 months. The common SGTs identified were 6, 19, 14 and 15. SGT 1, which was a common invasive isolate in children in our hospital during this period, was not isolated from these children. Sequential colonization by 2, 3 or 4 SGTs was observed in 18, 5 and 2 children, respectively. Resistance to penicillin, chloramphenicol, cotrimoxazole and erythromycin was observed in 0, 13 (6%) 11 (5 %) and 5 (3 %) isolates, respectively. There was a significant difference in susceptibility to cotrimoxazole between colonizing and invasive isolates (5 % vs. 40 %, P<0.0001).

Contribution of Streptococcus anginosus to infections caused by groups C and G streptococci, southern India.

This neglected pathogen causes a large portion of these infections.

PREVALENCE OF INDUCIBLE CLINDAMYCIN RESISTANCE IN GRAM POSITIVE ORGANISMS IN A TERTIARY CARE CENTRE

Gram positive organisms are one of the leading pathogens causing skin and soft tissue infections. For these infections, clindamycin is a useful alternate drug in penicillin-allergic patients. This study was conducted to investigate the prevalence of erythromycin-induced clindamycin resistance in gram positive organisms in the southern part of the country. A total of 522 consecutive clinical isolates from blood, CSF, sputum, throat, pus, and urine were collected between November 2006 and April 2007 and tested for erythromycin resistance and inducible clindamycin resistance. There was a relatively higher incidence of inducible clindamycin resistance among the MRSA isolates. We conclude, therefore, that clindamycin is not a suitable alternative antibiotic for use in staphylococcal skin and soft tissue infections.

Rheumatic Heart Disease: Progress and Challenges in India

Rheumatic heart disease, a neglected disease, continues to be a burden in India and other developing countries. It is a result of an autoimmune sequalae in response to group A beta hemolytic streptococcus (GAS) infection of the pharynx. Acute rheumatic fever (RF), a multisystem inflammatory disease, is followed by rheumatic heart disease (RHD) and has manifestations of joints, skin and central nervous system involvement. A review of epidemiological studies indicates unchanged GAS pharyngitis and carrier rates in India. The apparent decline in RHD rates in India as indicated by the epidemiological studies has to be taken with caution as methodological differences exist among studies. Use of echocardiography increases case detection rates of RHD in population surveys. However, the significance of echo based diagnosis of carditis needs further evaluation to establish the significance. Research in this area through prospective follow up studies will have to be undertaken by the developing countries as the interest of developed countries in the disease has waned due the declined burden in their populations. Prevention of RHD is possible through treatment of GAS pharyngitis (primary prophylaxis) and continued antibiotic treatment for number of years in patients with history of RF to prevent recurrences (secondary prophylaxis). The cost effectiveness and practicality of secondary prophylaxis is well documented. The challenge to any secondary prophylaxis program for prevention of RF in India will be the availability of benzathine penicillin G and dissipation of fears of allergic reactions to penicillin among practitioners, general public and policy makers. The authors review here the progress and challenges in epidemiology, diagnosis and primary and secondary prevention of RF and RHD.

One year trends in the gram-negative bacterial antibiotic susceptibility patterns in a medical intensive care unit in South India

PURPOSE To describe the changes in antibiotic susceptibility patterns of common intensive care unit pathogens with time from the medical intensive care unit of a tertiary care hospital. METHODS A prospective observational study was conducted in the medical intensive care unit (MICU) of a 2100 bed tertiary care hospital in South India. All data regarding patient characteristics, disease characteristics, infective agents, identified along with their antibiotic sensitivity patterns and patient outcomes were prospectively recorded in MICU data base. Various bacterial pathogen antibiotic sensitivity patterns from August 2004 to May 2005 were prospectively documented. During this period 491 patients were admitted to the MICU. Data were analyzed using excel spreadsheets. RESULTS Ceftazidime resistance reduced in Klebsiella spp. while cefotaxime resistance increased. In E. coli however, ceftazidime and cefotaxime resistance increased. Klebsiella resistance to cefotaxime and ceftazidime ranged from 25-50% and 14-91%, while E. coli resistance to these antibiotics ranged from 50-70% and 50 to 80% respectively. In Pseudomonas and the non-fermenting gram-negative bacteria (NFGNB) ceftazidime resistance decreased. Third generation cephalosporin resistance seemed to be reducing in the NFGNB, however, carbapenem resistance appeared to be increasing, possibly due to their increasing use. CONCLUSIONS This study demonstrates the trend in antibiotic susceptibility pattern (AST) of common gram negative infections seen in intensive care units. It demonstrates the changes seen especially after a change in the protocol antibiotic. Changes in the AST patterns of Klebsiella, E. coli, Pseudomonas and non-fermenting gram negative bacteria were seen. The data on the changing antibiotic susceptibility trends we believe is an important pillar in our efforts at infection control especially in intensive care settings.

Region specific and worldwide distribution of collagen-binding M proteins with PARF motifs among human pathogenic streptococcal isolates.

Some of the variety of Streptococcus pyogenes and Streptococcus dysgalactiae ssp. equisimilis (SDSE) M proteins act as collagen-binding adhesins that facilitate acute infection. Moreover, their potential to trigger collagen autoimmunity has been implicated in the pathogenesis of acute rheumatic fever and attributed to a collagen-binding motif called PARF (peptide associated with rheumatic fever). For the first time we determine the rate of clinical isolates with collagen-binding M proteins that use a PARF motif (A/T/E)XYLXX(L/F)N in a defined geographic region, Vellore in South India. In this region both, incidence of streptococcal infections and prevalence of acute rheumatic fever are high. M proteins with PARF motif conferred collagen-binding activity to 3.9% of 153 S. pyogenes and 10.6% of 255 SDSE clinical isolates from Vellore. The PARF motif occurred in three S. pyogenes and 22 SDSE M protein types. In one of the S. pyogenes and five of the SDSE M proteins that contained the motif, collagen-binding was impaired, due to influences of other parts of the M protein molecule. The accumulated data on the collagen binding activity of certain M protein types allowed a reanalysis of published worldwide emm-typing data with the aim to estimate the rates of isolates that bind collagen via PARF. The results indicate that M proteins, which bind collagen via a PARF motif, are epidemiologically relevant in human infections, not only in Vellore. It is imperative to include the most relevant collagen-binding M types in vaccines. But when designing M protein based vaccines it should be considered that collagen binding motifs within the vaccine antigen remain potential risk factors.

Transmission dynamics of methicillin-resistant Staphylococcus aureus in a medical intensive care unit in India.

Background Methicillin-resistant Staphylococcus aureus (MRSA) is a global pathogen and an important but seldom investigated cause of morbidity and mortality in lower and middle-income countries where it can place a major burden on limited resources. Quantifying nosocomial transmission in resource-poor settings is difficult because molecular typing methods are prohibitively expensive. Mechanistic statistical models can overcome this problem with minimal cost. We analyse the transmission dynamics of MRSA in a hospital in south India using one such approach and provide conservative estimates of the organisms economic burden. Methods and Findings Fifty months of MRSA infection data were collected retrospectively from a Medical Intensive Care Unit (MICU) in a tertiary hospital in Vellore, south India. Data were analysed using a previously described structured hidden Markov model. Seventy-two patients developed MRSA infections and, of these, 49 (68%) died in the MICU. We estimated that 4.2% (95%CI 1.0, 19.0) of patients were MRSA-positive when admitted, that there were 0.39 MRSA infections per colonized patient month (0.06, 0.73), and that the ward-level reproduction number for MRSA was 0.42 (0.08, 2.04). Anti-MRSA antibiotic treatment costs alone averaged

Clinical and Microbiologic Characteristics of Invasive Streptococcus pyogenes Infections in North and South India

124/patient, over three times the monthly income of more than 40% of the Indian population. Conclusions Our analysis of routine data provides the first estimate of the nosocomial transmission potential of MRSA in India. The high levels of transmission estimated underline the need for cost-effective interventions to reduce MRSA transmission in hospital settings in low and middle income countries.

Evaluation of simplified dna extraction methods for EMM typing of group a streptococci

ABSTRACT The lack of epidemiologic data on invasive Streptococcus pyogenes infections in many developing countries is concerning, as S. pyogenes infections are commonly endemic in these areas. Here we present the results of the first prospective surveillance study of invasive Streptococcus pyogenes infections in India. Fifty-four patients with invasive S. pyogenes infections were prospectively enrolled at two study sites, one in the north and one in the south of India. Sterile-site isolates were collected, and clinical information was documented using a standardized questionnaire. Available acute-phase sera were tested for their ability to inhibit superantigens produced by the patients own isolate using a cell-based neutralizing assay. The most common clinical presentations were bacteremia without focus (30%), pneumonia (28%), and cellulitis (17%). Only two cases of streptococcal toxic shock syndrome and no cases of necrotizing fasciitis were identified. Characterization of the isolates revealed great heterogeneity, with 32 different emm subtypes and 29 different superantigen gene profiles being represented among the 49 sterile-site isolates. Analyses of acute-phase sera showed that only 20% of the cases in the north cohort had superantigen-neutralizing activity in their sera, whereas 50% of the cases from the south site had neutralizing activity. The results demonstrate that there are important differences in both clinical presentation and strain characteristics between invasive S. pyogenes infections in India and invasive S. pyogenes infections in Western countries. The findings underscore the importance of epidemiologic studies on streptococcal infections in India and have direct implications for current vaccine developments.