Geeta Mehta

Computer assisted analysis of wound infection in neurosurgery

The effect of 10 variables on the development of postoperative infection in 536 clean elective neurosurgery patients was calculated using correlational, regression and discriminant analyses. The time of shaving the operation site, type of theatre ventilation and duration of operation were found to have a highly significant effect on the infection rate. The influence of season and age of patient was not evident on simple analysis, but both were found to be significant factors using regression analysis. The sex of patient, carriage of Staphylococcus aureus, airborne bacterial count, presence of bacteria in the wound and the use of prophylactic antibiotics did not have a significant effect on infection rates.

Clinico-Bacteriological Study of Pyodermas in Children

One hundred cases of pyodermas in children were investigated clinically and bacteriologically. Nasal and throat swabs from all cases were subjected to bacteriological examination. Most of the children (42%) were in the 1–4 year age group. The majority (58%) belonged to lower socio‐economic groups with poor standards of hygiene. A history of overcrowding was obtained from 87% of cases, 82% were undernourished. Most of the children (68%) reported during the hot and humid months of June, July, August, and September. Primary pyodermas were observed in 72% of the children, and secondary pyodermas in 28%. Impetigo was the commonest primary pyoderma (48.61%); among secondary pyodermas, infected scabies was noted predominantly (42.86%). The face and legs were more commonly involved.

Bacterial colonization of rings and cell phones carried by health-care providers: are these mobile bacterial zoos in the hospital?

Our objective was to assess the presence of pathogenic organisms on the rings (worn on fingers) and cell phones carried by health-care workers (HCWs) and the public. Forty-two percent of mobile phones carried by HCWs and 18% carried by the general public were found to carry one or more organisms; 82% of the rings worn by HCWs and 36% of those worn by the general public were found to be positive for the presence of at least one type of microbe.

Columnar defect induced phase transformation in epitaxial La0.7Ca0.3MnO3 films

Epitaxial La0.7Ca0.3MnO3 thin films on the SrTiO3(100) surface have been irradiated with 250 MeV Ag17+ ions at different nominal fluence values in the range of 5×1010–4×1011 ions/cm2, resulting in columnar defects. At low fluences these defects cause changes in material properties that are small and scale linearly with dosage. Above a threshold fluence value ∼3×1011 ions/cm2 dramatic changes are observed, including an order of magnitude increase in the resistivity and 50 K drop in the Curie temperature. Transmission electron microscopy measurements show that the changes are associated with a phase transformation of the undamaged region between the columnar defects. The transformed phase has a diffraction pattern very similar to that seen in charge-ordered La0.5Ca0.5MnO3. We propose that above a critical level of ion damage, strains caused by the presence of the columnar defects induce a charge-ordering phase transition that causes the observed dramatic changes in physical properties. We speculate that a c...

Multi-resistant Staphylococcus haemolyticus in a neonatal unit in New Delhi

We describe a cluster of infections in a neonatal nursery due to an infrequently reported staphylococcal species, Staphylococcus haemolyticus. S. haemolyticus resistant to penicillin, methicillin, gentamicin, erythromycin, chloramphenicol and tetracycline (PMGECT) was isolated from a series of infections in neonates (conjunctivitis 6, blood 2, pustules 2) over a period of 3 weeks in a neonatal nursery. Surveillance cultures from 22 neonates, their mothers in an adjacent maternity ward and staff revealed that S. haemolyticus with three resistance patterns (PMGECT, PMG and PME) was circulating in the unit. It was isolated from two caesarian wounds, the nose/ear/umbilicus of six asymptomatic infants and from the noses of three mothers and one nurse. S. haemolyticus showed a higher frequency of resistance to antibiotics than Staphylococcus aureus and Staphylococcus epidermidis isolated from the unit at the same time. Local and asymptomatic infections were treated with local neosporin application whereas netilmicin was used to treat systemic infection. Infections were controlled by emphasising the importance of handwashing, asepsis and eye care.

Observations on coagulase-negative staphylococci in a neonatal unit in India

Fifty neonates were included in a prospective study which determined the frequency of colonization and infection with coagulase-negative staphylococci (CNS) in a neonatal unit. The isolates were characterised by species, antibiotic resistance and ability to produce slime. Twenty-four epidemiologically related isolates (including four isolates from the hands of staff) were also phage typed and had plasmid analysis performed. On the first day of birth, 18% of infants were colonized with CNS, 40% and 30% by days 3-5 and day 7 respectively, and 25% by the 14th day and beyond. Staphylococcus haemolyticus and S. epidermidis were the most frequent CNS species encountered, accounting for 36% and 35% of isolates. Resistance to four or more antibiotics was present in 37% of strains isolated on the first day and this increased to 100% of isolates from infants who stayed for more than 14 days. Forty-five percent of CNS were slime producers; no significant difference was observed in slime producing ability between the species or isolates at different days after birth. Five infants developed septicaemia due to CNS. Staphylococcus haemolyticus and S. epidermidis were recovered as the only pathogens from three and two cases respectively. Detailed typing revealed that one case of infection with S. haemolyticus was preceded by surface colonization with an identical strain. Evidence was also obtained for the transmission of CNS between babies on the hands of staff.

Risk Factor Analysis and Microbial Etiology of Surgical Site Infections following Lower Segment Caesarean Section

Background. Lower segment caesarean section (LSCS) is a common mode of delivery now and surgical site infection is the second most common infectious complication in these patients. This study was planned with this background to have a comprehensive approach to SSI following LSCS. Methods. 500 consecutive patients undergoing LSCS, irrespective of indication, were studied. A questionnaire was developed to assess the risk factors associated with development of SSI. All patients were followed up from day one of surgery till discharge and then up till the postoperative day 30 after discharge. Results. SSI was identified in 121 (24.2%) out of 500 patients. In all age groups, Gram-negative bacilli were the commonest finding. The commonest isolate was Acinetobacter species (32.03%) followed by Staphylococcus aureus and coagulase negative Staphylococcus (21.09%). 23.8% of Staphylococcus aureus strains were MRSA. By multivariate logistic regression premature rupture of membrane (PROM), antibiotics given earlier than 2 hours and increased duration of stay in the hospital were found to be significant. Conclusions. A proper assessment of risk factors that predispose to SSI and their modification may help in reduction of SSI rates. Also, frequent antimicrobial audit and qualitative research could give an insight into the current antibiotic prescription practices and the factors affecting these practices.

Postoperative infection in cardiac surgery: the influence of a change in prophylactic antibiotic regimen

A total of 448 patients undergoing cardiovascular surgery were followed for the development of postoperative infection. Non-extracorporeal procedures were assigned to group 1 and open-heart procedures to group 2. The incidence of infection was compared in two groups who received prophylactic antibiotics. Patients (n = 253) received ampicillin alone (group 1) or in combination with gentamicin (group 2) for 7 days starting 1 day before the operation (period A). One hundred and ninety-five patients (period B) received cefazolin starting preoperatively 30 min before induction, alone (group 1) or in combination with gentamicin (Group 2) for 3 days. The percentage of patients developing infection in periods A and B for group 1 patients was 4.2% and 3.5% and for group 2 it was 25.8% and 18.7% respectively. The overall infection rate was 13%. The number of infection sites involved were 1.5 per infected patient. Urinary tract infections were the most frequent followed by endocarditis and other deep infections, wound infections and respiratory infection. Gram-negative rods were the predominant pathogens (Klebsiella spp. and Pseudomonas aeruginosa) during both periods (47 out of 70 isolates). Wound infections due to Gram-positive cocci were higher in period A (4/8) as compared to period B (1/5). During period B there were three cases of fungal endocarditis whereas no case occurred during period A. Although the incidence of infection was reduced during the period of cefazolin prophylaxis, the difference was not statistically significant.

Asymptomatic Salmonella senftenberg carriage in a neonatal ward

During a 23-day period in April 1991, nine infants in a neonatal ward were found to be colonized with Salmonella senftenberg. All were asymptomatic on detection and all except one (who developed septic ileus) remained asymptomatic on follow-up. The affected babies were isolated and subsequently discharged from the ward as soon as possible. These measures, along with emphasis on handwashing and intensification of cleaning and disinfection, were able to prevent spread to other babies. Despite extensive sampling of the environment, mothers and staff, the source of the organism could not be identified.

Molecular epidemiology and virulence characteristics of prevalent group A streptococci recovered from patients in northern India

INTRODUCTION In this study, the prevalence of M types of Group A Streptococcus (GAS) in North India, invasive behavior of prevalent M types, and inflammatory immune response by host cells were studied. METHODOLOGY A total of 1,047 clinical samples were collected between 2004 and 2010. Confirmation of GAS was determined by serotyping and M types were identified by emm gene sequencing. The most prevalent serotypes were selected to study their invasive behavior and inflammatory immune response under different temperatures and salt concentrations in A549 and HEp-2 cells. RESULTS Ninety-two isolates were identified as GAS of which 17 were M types with 18.5% heterogeneity. The most prevalent M types were M1 (21.73%) and M49 (8.7%), respectively. M1 and M49 were used to study virulence potential and inflammatory immune responses. The efficiency of cell infection decreased with increased temperature for both M types, increasing with lowering temperatures compared to the uninfected control (37°C). As salt concentration was increased, cell infection efficiency was lowered with some exceptions; the infection efficiency of M1 strain in A549 cells with 0.6 M NaCl was 50 fold higher (p ≤ 0.03). Significantly increased production of IL-6 and IL-8 was observed in both cell lines infected with GAS and when grown under different environmental conditions compared to uninfected cell lines. CONCLUSIONS This study determined the prevalence of different M types in North India and showed that environmental conditions can regulate cell infection by GAS . This information may influence the selection of GAS serotypes used in vaccine development.