Detection of clindamycin susceptibility in macrolide resistant phenotypes of Staphylococcus aureus

The present study aimed at in vitro detection of macrolide resistant phenotypes of methicillin resistant Staphylococcus aureus (MRSA) and interpretation of susceptibility tests to guide therapy. The study included 25 MRSA strains that were resistant to erythromycin and clindamycin, 25 MRSA strains that were sensitive to both erythromycin and clindamycin and 100 MRSA isolates which displayed erythromycin resistant but clindamycin susceptible phenotype. Erythromycin and clindamycin double disc susceptibility testing was done to detect inducible clindamycin resistance. Dilution susceptibility testing for clindamycin and erythromycin alone and in combination was performed for all 150 strains. Seventy-six strains showed blunting around clindamycin disc (inducible resistance). After induction with erythromycin, minimum inhibitory concentration (MIC) of clindamycin was noticed to rise from at least 16 to 256 g/mL in iMLSB phenotypes indicating inducible resistance. The detailed result analysis suggests the possible role of clindamycin in treatment of some of the erythromycin resistant isolates (non inducible), as there are multiplicity of resistance mechanisms and diversity of phenotypic expressions.

Alterations in expression of retinoid receptor beta and p53 in oral submucous fibrosis

OBJECTIVE

Knowledge of the molecular pathogenesis of oral submucous fibrosis (OSF), a potentially malignant condition with high risk of transition to oral cancer, is meagre. Alterations in the expression of retinoic acid receptor beta (RARbeta) and tumor suppressor gene, p53 are early events in oral tumorigenesis. The aim of this study was to investigate the alterations in the expression of RARbeta and p53 in OSF lesions and determine their association with disease pathogenesis.

METHODS

The expression of RARbeta and p53 proteins was analyzed by immunohistochemistry in 50 cases of OSF and 30 histologically normal oral tissues.

RESULTS

No detectable RARbeta expression was observed in 35 of 50 (70%) OSF cases. p53 protein accumulation was observed in 24 of 50 (48%) OSF cases analyzed. Thirty-six percent OSF lesions showed loss of RARbeta and p53 overexpression. Interestingly, 41 of 50 (82%) of OSF lesions showed altered expression of at least one of these two proteins.

CONCLUSION

Altered expression of either RARbeta or p53 in majority of OSF lesions suggests their association with disease pathogenesis and warrants follow-up to determine whether OSF lesions harboring concomitant alterations in RARbeta and p53 are at a high risk of transition to malignancy.

Selective transmission of multidrug resistant HIV to a newborn related to poor maternal adherence

OBJECTIVES

To report perinatal transmission of multidrug resistant (MDR) HIV related to variable maternal adherence antenatally.

METHODS

Case study including review of clinic records, adherence information, laboratory data, and HIV genotyping results in mother and infant.

RESULTS

Poor maternal adherence to clinic visits and antiretroviral therapy contributed to detectable viraemia antenatally. When tested for the first time at age 6 months, the infant was found to have virus with resistance to multiple drugs. In this case, prophylaxis with zidovudine (AZT) failed to prevent the transmission of the MDR strain.

CONCLUSIONS

Perinatal transmission of MDR HIV can occur despite standard peripartum prophylaxis with AZT. Perinatal prophylaxis should be tailored to the mother's treatment history and resistance profile. Paediatric HIV specialists should be prepared to deal with a small, but slowly increasing number of babies with a "nightmare" multidrug resistant virus with limited treatment options.

Evaluation of the direct acridine orange staining method and Q.B.C. test for diagnosis of malaria in Delhi, India

Conventional Giemsa stained peripheral blood smear examination for demonstration of malarial parasites remains the gold standard for diagnosis of malaria in developing endemic countries. However this technique is time consuming, requires training and may give poor results in cases with low parasitaemia. To overcome these problems and improve diagnostic accuracy two newer tests have been studied and compared with standard Giemsa staining. These are the wet mount fluorescence microscopy of Acridine Orange stained thin blood films (A.O.) and the Quantitative Buffy Coat technique (Q.B.C) for diagnosis of malaria. A.O. staining was found to be 97.5% sensitive and 100% specific for detection of all stages and species of malarial parasite. The Q.B.C assay was found to be 100% sensitive and 97.5% specific for diagnosis of malaria. A.O. staining was very fast and the species identification was easy once the staining was optimised. The Q.B.C. test required considerable amount of practice, costly equipment, however it was fast and in our study was found to be highly sensitive.

Use of a new medium - tobacco agar, for pigment production of Cryptococcus neoformans

Cryptococcus neoformans produces brown colonies on Niger seed (Guizotia abyssinica) agar. Media containing caffeic acid, L-dopa and other diphenolic compounds, have been used for the same purpose. The present report describes a new medium containing tobacco which supports growth of C.neoformans and allows its easy differentiation by formation of brown coloured colonies.

Vibrionaceae from cases of acute diarrhoea and their antimicrobial sensitivity pattern - a five year prospective study

Over a five year period, stool samples were screened for Vibrionaceae from cases of acute diarrhoea, to study their isolation rate and their antimicrobial sensitivity pattern. All the isolates were identified by standard laboratory techniques. A total of 323 species belonging to Vibrionaceae were isolated from 4492 stool samples tested over five year period (1996-2000), giving a positivity rate of 7.2%. Maximum isolation was during the months of May to August (62.5%). Out of 323 isolates, Vibrio spp. comprised 252 and 93.3% of them were Vibrio cholerae O1 biotype El Tor. Aeromonas spp. were isolated from 71 samples and 64.8% of them were A. hydrophila. V. cholerae showed 86.8% sensitivity to amikacin followed by 73.8% to cefotaxime. Tetracycline sensitivity was only 39.6%. Aeromonas spp. also showed maximum sensitivity to amikacin (70.4%). Isolation of Vibrio spp. have increased over the years, whereas Aeromonas spp. have decreased. Amikacin sensitivity has remained within 70-80% over the years, cefotaxime sensitivity has increased and tetracycline sensitivity has decreased.

Bacteriological studies of gas gangrene and related infections

Gas gangrene, a life threatening condition is predominantly caused by Clostridium spp. Over a five year period (1996-2000), 580 wound swabs were processed from patients who had vehicular accidents with crush injury. The specimens were processed for anaerobic and aerobic organisms by standard laboratory techniques. Of the 580 swabs, 55(9.48%) were primary smear positive for spore bearing bacteria, of which 48 grew Clostridium spp. They were the sole anaerobic isolates in 30 patients (62.5%) whereas Clostridium spp. along with nonsporing anaerobes were isolated in 18 patients. Clostridium perfringens was the predominant isolate in 39 out of 48 cases (81.3%). However, 16 wound swabs which were primarily smear negative for spore bearers, grew Bacteriodes fragilis (11) and Fusobacterium species (5). All these 16 patients had foul smelling discharge with crepitation in the tissues. Our study highlights that apart from Clostridium spp., non-clostridial crepitant infections may present as myonecrosis simulating gas gangrene.

Seroprevalence of torch infection in bad obstetric history

Primary infection with TORCH complex [Toxoplasma, Rubella, Cytomegalovirus (CMV), and Herpes simplex virus II (HSV-II)] in pregnant women can lead to adverse outcome which are initially inapparent or asymptomatic and thus difficult to diagnose on clinical grounds. Over a one-year period 380 serum samples were collected from pregnant women having bad obstetric history, attending antenatal clinic. In the present study we have shown the prevalence of Toxoplasma, Rubella, CMV, HSV-II infection in pregnant women by demonstrating the presence of IgM and IgG antibodies by ELISA test. It was found that, IgM antibodies were positive in 40 (10.52%) for Toxoplasma, 102 (26.8%) for Rubella, 32 (8.42%) for CMV and 14 (3.6%) for HSV-II. IgG antibodies were positive in 160 (42.10%) for Toxoplasma, 233 (61.3%) for Rubella, 346 (91.05%) for CMV 145 (33.58%) for HSV-II. Hence all antenatal cases with bad obstetric history should be routinely screened for TORCH as early diagnosis and appropriate intervention, will help in proper management of these cases.

Sacrococcygeal teratoma with anorectal malformation

A 7-month-old child presented with imperforate anus, penoscrotal hypospadias and transposition, and a midline mucosa-lined perineal mass. At surgery the mass was found to be supplied by the median sacral artery. It was excised and the anorectal malformation was repaired by posterior sagittal anorectoplasty. Histologically the mass revealed well-differentiated colonic tissue. The final diagnosis was well-differentiated sacrococcygeal teratoma in association with anorectal malformation.

Risk of needle stick injuries in health care workers - a report

Health care workers (HCW) are at a risk of occupational acquisition of Human Immunodeficiency Virus (HIV) infection, primarily due to accidental exposure to infected blood and body fluids. In our general public hospital, over a period of one year (June 2000 - 2001) a total number of 38 self reported incidences of needlestick injuries and other exposures to patient's blood and body fluids were reported by HCWs. A greater incidence of occupational exposure was seen in surgery residents as compared to medicine residents. Till date, i.e. in one and a half-year follow up period, no seroconversion was seen in any of the reported accidental injury cases. This data emphasizes, that needle stick injuries present the single greatest risk to medical personnel and the importance of increased awareness and training in universal safety precautions (USP), for prevention of nosocomial infection.

A clinicopathological study of acute necrotising jejunoileitis

We describe a variety of acute necrotizing enteritis that is endemic to the Indian subcontinent. During the period 1992-1998, 18 cases of acute jejunoileitis (AJI) were managed. Only those in whom the diagnosis was confirmed at laparotomy have been included in this study. The most common symptoms were abdominal pain (100%), fever (77%), and blood in the stool (100%). A stricture following conservative treatment was present in 1 case. The mean age at presentation was 6.5 years (range 6 months-12 years); the male:female ratio was 1.2:1. All cases were seen during May-October. Routine investigations and X-ray films were nonspecific. Stool cultures did not show any clostridia, shigella, or salmonella. The jejunum was involved most commonly; 28% of patients did not require a bowel resection. Only 1 child presented with shock; the mortality was less than 5%. Short-bowel syndrome resulted in 1 patient due to extensive disease. The histopathologic features that were characteristic of the disease were patchy transmural mucosal necrosis extending centrifugally with submucosal edema, interstitial hemorrhage, type III hypersensitivity reaction, and extensive neovascularization. This type of AJI seen in South/Southeast Asia does not seem to be due a to bacterial infective etiology; immune mediation is suggested. The milder forms can be confused with dysentery. Mild forms of the disease can be managed conservatively, but carry the risk of developing strictures. This disease should be suspected in cases of prolonged dysentery during the summer and autumn months.

Colonisation of methicillin resistant Staphylococcus aureus among health care workers in a tertiary care hospital of Delhi

Methicillin resistant strains of Staphylococcus aureus have been responsible for many nosocominl epidemics. Colonised employees of hospital such as asymptomatic nasal and hand carriers act as reservoirs for the spread of this organism within hospital. During a period of three months 150 HCW were screened for nasal and hand colonisation by MRSA. 6.6% (10) HCW were colonised by MRSA and 50% of these were carrying MRSA on both hands and anterior nares. 30% (3) of MRSA strains were multidrug resistant and 60% (6) were resistant to ciproflox. Whether the eradication of MRSA carrier state will lead to decreased rate of MRSA infection is yet to be documented.

Anaerobes in pleuropulmonary infections

A total of 76 anaerobes and 122 aerobes were isolated from 100 patients with pleuropulmonary infections, e.g. empyema (64), pleural effusion (19) and lung abscess (13). In 14% of the patients, only anaerobes were recovered, while a mixture of aerobes and anaerobes was encountered in 58%. From all cases of lung abscess, anaerobic bacteria were isolated, alone (04) or along with aerobic bacteria (13). From empyema and pleural effusion cases, 65.6% and 68.4% anaerobes were recovered respectively. Amongst anaerobes, gram negative anaerobic bacilli predominated (Prevotella melaninogenicus 16, Fusobacterium spp. 10, Bacteroides spp. 9), followed by gram positive anaerobic cocci (Peptostreptococcus spp. 31). Coliform bacteria (45) and Pseudomonas aeruginosa (42) were the predominant aerobic isolates.

An outbreak of leptospirosis in Mumbai

Following prolonged water logging due to heavy rainfall in Mumbai during July 2000, a total of 102 patients clinically suspected of leptospirosis were admitted in our hospital. Blood samples were examined for the presence of leptospires by dark ground microscopy (DGM) and IgM antibodies were detected by ELISA. Out of 102 blood samples, 37 were positive by ELISA giving a positivity rate of 36.27%. Of these, only 24 were positive by DGM. Out of the positive cases, 37.83% had respiratory symptoms, 32.43% each had jaundice and conjunctival suffusion and 16.21% had renal involvement. Mortality amongst the positive cases was 10.81%. Apart from hepatic and renal involvement, respiratory symptoms due to leptospirosis are on the rise.

Prognostic factors in betel and tobacco related oral cancer

Paucity of well-defined prognostic molecular markers severely hampers prediction of the clinical course of squamous cell carcinoma (SCC) of oral cavity. The aim of the study was to evaluate the prognostic significance of impairments in the expression of proteins involved in cell cycle regulation and locoregional spread in oral SCC of habitual betel and tobacco chewers. A prospective study was performed in 105 betel and tobacco consumers with oral SCCs during the period 1988-1999, to evaluate the prognostic relevance of impairments in the expression of proteins involved in cell cycle regulation and locoregional spread. Alterations in the expression of p53, pRb, p16, MDM2, p21, and Ets-1 proteins were determined by immunohistochemical analysis in formalin fixed, paraffin embedded tissue sections from oral SCCs. Analysis of multiple molecular biological factors showed overexpression of p53 in 69/105 (66%) cases, MDM2 in 72/105 (69%) cases, p21 in 57/105 (54%) cases and Ets-1 in 64/105 (61%) cases. Loss of pRb was observed in 58/105 (55%) cases and p16 loss was observed in 72/105 (69%) cases. Interestingly, multivariate analysis revealed loss of pRb as the most significant predictor of advanced tumour stage [P=0.001; Odd's Ratio (OR)=3.5] and overexpression of Ets-1 protein was an independent risk factor for lymph node metastasis (OR: 10.1; P<10(-6)). Multiple logistic regression models showed that pRb loss [Hazard's Ratio (HR): 3.93] and p53 overexpression (HR: 2.97) may serve as adverse prognosticators for disease free survival of the patients. The data demonstrate multiple impairments in p53/MDM2/p21/Ets-1 and p16/pRb pathways in betel and tobacco related oral tumourigenesis.