Low-level quinolone-resistance in multi-drug resistant typhoid

To find out the frequency of low-level quinolone-resistance in Multi-Drug Resistant [MDR] typhoid using nalidixic acid screening disc. Descriptive study. Armed Forces Institute of Pathology, Rawalpindi, from January 2005 to December 2005. Blood was obtained from suspected cases of typhoid fever and cultured in to BacT/ALERT. The positive blood cultures bottles were subcultured. The isolates were identified by colony morphology and biochemical tests using API-20E galleries. Susceptibility testing of isolates was done by modified Kirby-Bauer disc diffusion method on Muellar Hinton Agar. For the isolates, which were resistant to nalidixic acid by disc diffusion method, Minimal Inhibitory Concentrations [MICs] of ciprofloxacin and nalidixic acid were determined by using the E-test strips. Disc diffusion susceptibility tests and MICs were interpreted according to the guidelines provided by National Committee for Control Laboratory Standard [NCCLS]. A total of 21[65.5%] out of 32 isolates of Salmonellae were nalidixic acid-resistant by disk diffusion method. All the nalidixic acid-resistant isolates by disc diffusion method were confirmed by MICs for both ciprofloxacin and nalidixic acid. All the nalidixic acid-resistant isolates had a ciprofloxacin MIC of 0.25-1Mu g/ml [reduced susceptibility] and nalidixic acid MICs = 32 Mu g [resistant]. Out of all Salmonella isolates, 24 [75%] were found to be MDR, and all were S. typhi. Low-level quinolone-resistance in typhoid was high in this small series. Screening for nalidixic acid resistance with a 30 Mu g nalidixic acid disk is a reliable and cost-effective method to detect low-level fluoroquinolone resistance, especially in the developing countries

Peripheral blood-based polymerase chain reaction in diagnosis of pulmonary tuberculosis

The rapid diagnosis of infectious diseases, particularly those that represent a public health problem, like tuberculosis, is a challenging problem. By using nucleic acid amplification techniques like PCR, one may be able to diagnose, the disease on the day of arrival of specimen in the laboratory. For diagnosis of tuberculosis by direct methods like PCR, specimens from site of infection are required. In certain cases it is difficult to get the specimens from site of infection and in such situations; some researchers have tried to detect the DNA of Mycobacterium tuberculosis complex from blood of these patients. The purposive of this study is to determine the diagnostic efficacy of peripheral blood-based polymerase chain reaction for diagnosis of pulmonary tuberculosis. This was a simple descriptive study, carried out in Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi from Jan 2004 to Dec 2004. Sputum and blood samples were collected from 96 suspected patients of pulmonary tuberculosis. Sputum samples processed for ZN staining and AFB culture [gold standard] and blood samples processed for PCR. Out of 96 cases, 60 [62.5%] were culture positive. PCR was positive in 14 [14.5%]. AFB smear positive were 34 [35.4%]. The overall sensitivity and specificity of the PCR assay was 20% and 94.4% respectively and the positive and negative predictive values were 85.71% and 41.46% respectively. The overall efficiency of the test was 47.91%. Due to low sensitivity; a negative PCR assay does not rule the disease. However, this test may be helpful in cases where specimens from the site of infection are not available

Seroprevalence of hepatitis B and C in young adults seeking recruitment in Armed Forces

Hepatitis B virus [HBV] and hepatitis C virus [HCV] are the commonest causes of chronic liver disease all over the world including Pakistan. According to the Pakistan Armed Forces policy, all the military recruits are now screened for the Hepatitis B surface antigen [HBsAg] and antibodies to Hepatitis C virus [Anti-HCV] before induction. Previous studies have shown a wide variation in the results regarding the prevalence of HBV and HCV infections. We analysed sera of 15550 young adults seeking recruitment in Armed forces for the presence of HBsAg and Anti-HCV. Sera of healthy adult individuals who presented for medical evaluation as prerecruitment criteria in the Punjab Regiment Centre, Mardan, were tested for presence of hepatitis B surface antigen [HBsAg] and anti-hepatitis C virus [Anti-HCV] by rapid method. Positive cases were confirmed by ELISA technique from Armed Forces Institute of Pathology [AFIP] Rawalpindi. A total of 15550 individuals were examined. Out of these, 504 [3.24%] individuals had positive HBsAg whereas 574 [3.69%] were positive for anti-HCV. Hepatitis B surface antigen and anti-HCV both were found in 49 [0.31%] individuals. This study which evaluated predominantly healthy young male population, showed a high seroprevalence of anti-HCV than Hepatitis B surface antigen. Although there is downward trend in prevalence of hepatitis B, there is considerable threat of HBV and HCV to our younger population and there is a genuine need for strict adherence to preventive measures

Microscopy of gram stained uncentrifuged drop of urine for presumptive diagnosis of urinary tract infections

To evaluate the diagnostic efficiency of microscopic examination of Gram stained uncentrifuged drop of urine for presumptive diagnosis of urinary tract infections [UTI]. 250 samples collected from March 2005 to August 2005 comprising of both in patient and out patient samples were analyzed. Urine sample was homogenized and a nickel-chrome loop, calibrated to 10 micro l was used to take a drop of urine and was applied on glass slide [25mm x 75mm]. The drop was allowed to dry in air at room temperature [25°C approx.] without spreading. The slides after drying were stained with Gram method of staining. The microscopic examination was carried out with a 100x oil immersion objective, 30 fields were examined. Observation of one or more microorganism per high power oil immersion lens was taken as a positive reading. Culture of urine was taken as reference method and performed by using filter paper strips applying 2micro l of urine on cystine-lactose-electrolyte-deficient agar. Culture results obtaining a mixed growth of >/= 2 organisms were excluded out of the study. Only those cultures were taken as positive and made part of the study which yielded more than 10[5] or 10[4] to 10[5] CFU of pure single type /ml of urine. Sensitivity, specificity, positive and negative predictive values were calculated by using appropriate formulas. A total of 250 samples were processed for the study. Out of which 39 [15.6%] samples yielded mixed growth of > 2 organisms. All these samples were excluded out of the study [remaining 211 samples]. Microscopic examination of 97[45.9%] samples showed no organism and no growth was obtained on subsequent culture of these samples [true negative]. 61 [28.9%] samples were found to have >/= 1 organism in Gram stained smear of uncentrifuged single drop of urine and their culture yielded growth of > 10[5] or 10[4] to 10[5] CFU of pure single type /ml of urine [true positive]. No organism was detected on microscopic examination of 9 [4.2%] samples however pure growth of single organism was obtained on their culture [false negative]. >/= 1 organisms were seen on the microscopic examination of 44 [20.8%] samples which failed to grow on culture media [false positive]. Sensitivity [87.1%], specificity [61 .39%], positive predictive value [58.09%], negative predictive value [91.5%] was calculated by using respective formulas. This method provides a good negative predictive value and helps to rule out the presence of UTI efficiently when bacteria are not seen on microscopic examination. A very simple method without the use of laboratory centrifuge and culture media makes it an ideal practice in peripheral laboratories devoid of adequate resources and facilities to deal with one of the most commonly received specimens

CTX-M ESBL enzyme in Escherichia coli from urology patients in Rawalpindi, Pakistan

To detect CTX-M phenotype utilizing disc diffusion and MIC testing in Escherichia coli isolated from a tertiary care urology setting. Fifty single, non duplicate ESBL producing isolates from a tertiary care urology hospital were evaluated for the presence of CTX-M phenotype. Initially all the urinary isolates were tested for ESBL production. The isolates were identified by using API 20E galleries and screened for ESBL production by combination disc. Representative 4 ESBL isolates were sent to Antibiotic Resistance Monitoring and Reference Laboratory [ARMRL], Health Protection Agency, Colindale, London, UK where those were further subjected to MIC testing by agar dilution and E-test strips. A total of 4 ESBL producing E. coli isolates were characterized to be CTX-M on phenotypic characterization. The overall yield of CTX-M phenotypes was 75%.The emergence of CTX-M from Pakistan is alarming; however, further studies are required to study the epidemiology and genetic characterization of CTX-M types of ESBLs

Changing frequencies and current status of multiple-drug resistant typhoidal salmonellae in year 2001-2003 at Rawalpindi

Typhoid fever is endemic in developing countries. Multiple drug resistant [MDR] typhoidal salmonellae are on the rise worldwide. We carried out a study in our setup to determine the changing frequencies of typhoidal salmonellae and to highlight their current antibiotic resistance patterns. The study was carried out on 15611 blood samples of admitted patients with febrile illness from 2001 to 2003. The blood culture samples were subcultured on Blood Agar and MacConkey Agar. Non lactose fermenting colonies were identified for typhoidal salmonellae and confirmed by using API 20E galleries and standard serological methods. Antibiotic susceptibility testing was performed using Modified Kirby-Bauer disk-diffusion method on Mueller-Hinton Agar. A total number of 333 isolates of Salmonella typhi and Salmonella paratyphi A were isolated from blood samples. Multidrug resistance was found in 172 [51.65%] isolates. The combined frequencies of MDR Salmonella typhi and MDR Salmonella paratyphi A decreased from 55.14% in year 2001 to 31.25% in year 2003 showing a decreasing trend. No Salmonella paratyphi B and Salmonella partyphi C were isolated in our study. None of the isolate was resistant to ciprofloxacin, ofloxacin and ceftriaxone. From 2001 to 2003, a changing trend in frequencies of MDR typhoidal Salmonella and reemergence of Salmonella typhi has been observed as compared to Salmonella paratyphi A. ciprofloxacin, ofloxacin and ceftriaxone are the drugs of choice for MDR typhoidal Salmonellae