Is seroprevalence of hepatitis B and C among blood donors changing in northern Pakistan?

Objective: To determine seroprevalence of hepatitis B and C among blood donors in 2009 and comparing with the seroprevalence in 2014

Study Design: Cross sectional study with retrospective data collection

Place and Duration of Study: Foundation University Medical College and Fauji Foundation Hospital, Rawalpindi. Data in 2009 and in 2014 were collected

Material and Methods: The blood samples collected from individuals from Province of Khyber Pakhtunkhawa, Azad Kashmir and Northern Punjab including Rawalpindi-Islamabad and comprised 3776 [in the year 2009] and 6740 [in the year 2014] adults ranging from 18 to 60 years who reported to Fauji Foundation Hospital, Rawalpindi voluntarily or as a compulsion to donate blood for their patients

Results: During 2009, there were 71 [1.88%] and 113 [2.99%] donors positive for hepatitis B surface antigen [HBsAg] and anti hepatitis C virus [Anti HCV] respectively out of a total of 3776 donors whereas during 2014 there were 106 [1.57%] and 174 [2.58%] donors positive for HBsAg and anti HCV respectively out of a total donors of 6740. There was no statistical significant difference between the year [2009 and 2014] and seroprevalence of HBsAg [p=0.239] and HCV positive donors [p=0.215]

Conclusion: There is no significant change in seroprevalence of hepatitis B and C among blood donors during 2014 as compared to 2009 in Northern Pakistan

Predicament in detection and reporting of extended spectrum beta lactamase production in routine antibiotic susceptibility testing

This descriptive and cross-sectional study was planned to determine the dilemma of inadvertent detection of extended spectrum beta lactamase [ESBL] production in Enterobacteriaceae when using inhibition zone size of antibiotic disks of Cefotaxime or Aztreonam in routine antibiotic susceptibility testing as recommended by Clinical Laboratory Standards Institute [CLSI]. Screening and double disk tests were adopted as per CLSI. Escherichia coli ATCC 25922 was used as control strain. Among total specimens of 5346, there were 348 isolates of Escherichia coli [n=235], Klebsiella pneumonia [n=92], Klebsiella oxytoca [n=3] or Proteus mirabilus [n=18]. The screening method recommended by CLSI significantly falsely detected ESBL production in 79 [32.3%] isolates [p<0.0001]. ESBL detection is important as its frequency is high and treatment of the infection varies with the presence and absence of ESBL. To avoid false reporting, proper phenotypic detection of ESBL confirmatory method-like double-disk synergy test, should be used routinely

Pre-analytical variation in glucose concentration due to atmospheric temperature and clot in blood specimens

Objective: To determine the effect of temperature and contact of clot with serum on laboratory results of glucose concentration in blood

Study Design: Quasi-experimental study

Place and Duration of Study: December 2014 to August 2015 at the laboratory of Shoaib Hospital, Fateh Jang, Attock Pakistan

Material and Methods: Samples were collected for estimation of blood glucose [Random] concentration from patients reporting to the hospital. Blood specimens [n=94] of such volunteers were analyzed for glucose level. Each sample was put up in five tubes. When the blood clotted the serum from tube-1 was analyzed for glucose level within 30 minutes. In tube-2 and tube-3 serum was kept for 24 hours at room temperature and refrigerator temperature respectively before glucose estimation. In tube-4 and tube-5 serum was not separated from clot and kept at room temperature and refrigerator temperature respectively before glucose estimation. The value of tube 1 was taken as reference value for comparison with other parts of the specimen. The equipment used for blood glucose level estimation was semi auto chemistry analyzer [Rayto, China]. The kit used for analysis was Glucose - Liquizyme [Germany]

Results: The difference between the mean reference value [tube-1] and refrigerated serum without clot [tube-3] was 4.63 mg/100 ml while that of unrefrigerated portion [tube-2] had a difference of 10.68 mg/100 ml. The mean of unrefrigerated [tube-4] and refrigerated [tube-5] portions of serum kept with the clot had difference of 42.05 mg/100 ml and 25.84 mg/100 ml respectively. The fall in the blood glucose level in all [n=94] the samples in the tube number 3 [serum separated and kept at refrigerated temperature] was 4.63 mg/100 ml +/- 3.68 [Mean +/- SD] and it ranged from 0 to 20 mg/100 ml whereas fall was maximum in the tube number 4 [serum with clotted blood and kept at room temperature] was 42.04 mg/100 ml +/- 10.61 [Mean +/- SD] and it ranged from 13 to 82 mg/100 ml. The sample in tube 3 provided the best results as compared to all the other tubes [p=<0.0001]. When the serum was kept with clot there was significantly lesser fall when the sample was kept at refrigerated temperature [tube 4] than at room temperature [tube 5] [p=<0.0001]. When comparing the fall in blood glucose in sample kept at room temperature but clot separated [tube-2] with sample kept at refrigerated temperature but clot was not separated [tube-5] there was a significantly less fall in glucose in tube-2 [p=<0.0001] indicating that reduction factor of clot is more contributor than the temperature

Conclusion: There is maximum resistance in fall in glucose level after 24 hours when the blood sample was kept at refrigerated temperature and clot was removed before preservation. If refrigeration facilities are not available, it would be appropriate to remove clot before preservation at room temperature to get the consistent results as far as possible

Clinical Application of AIMS65 Scores to Predict Outcomes in Patients with Upper Gastrointestinal Hemorrhage

BACKGROUND/AIMS: To evaluate the ability of the recently proposed albumin, international normalized ratio (INR), mental status, systolic blood pressure, age >65 years (AIMS65) score to predict mortality in patients with acute upper gastrointestinal bleeding (UGIB). METHODS: AIMS65 scores were calculated in 251 consecutive patients presenting with acute UGIB by allotting 1 point each for albumin level 1.5, alteration in mental status, systolic blood pressure or =65 years. Risk stratification was done during the initial 12 hours of hospital admission. RESULTS: Intensive care unit (ICU) admission, endoscopic therapy, or surgery were required in 51 patients (20.3%), 64 (25.5%), and 12 (4.8%), respectively. The predictive accuracy of AIMS65 scores > or =2 was high for blood transfusion (area under the receiver operator characteristic curve [AUROC], 0.59), ICU admission (AUROC, 0.61), and mortality (AUROC, 0.74). The overall mortality was 10.3% (n=26), and was 3%, 7.8%, 20%, 36%, and 40% for AIMS65 scores of 0, 1, 2, 3, and 4, respectively; these values were significantly higher in those with scores > or =2 (30.9%) than in those with scores or =2 predict high in-hospital mortality.

Diagnostic yield of bronchoalveolar lavage gene xpert in smear-negative and sputum-scarce pulmonary tuberculosis

To measure the diagnostic yield of Bronchoalveolar Lavage [BAL] gene Xpert [Xpert MTB/RIF assay], to detect Mycobacterium tuberculosis [MTB] and rifampicin resistance and compare it with that of mycobacterial cultures in a suspected case of pulmonary tuberculosis. An analytical study. Department of Pulmonology, Fauji Foundation Hospital [FFH], Rawalpindi, from December 2012 to August 2013. BAL specimens of 93 patients with suspected pulmonary tuberculosis with smear-negative or sputumscarce disease, who presented to the Department of Pulmonology, FFH, Rawalpindi were inducted. A smear-negative case was one in whom three consecutive early morning sputum samples did not reveal acid fast bacilli when examined by microscopy with Zeihl Nelson [ZN] stain. Patients who had sputum amount less than 1 ml were defined to have sputumscarce disease. The same was evaluated with ZN stain, gene Xpert and mycobacterial cultures. Sensitivity analysis was carried out using culture as the gold standard. The frequency of positive mycobacterial cultures was 85 [91.4%]. The sensitivity, specificity, positive predictive value and negative predictive values of BAL gene Xpert to detect Mycobacterium tuberculosis were 91.86%, 71.42%, 97.53% and 41.66% respectively. Xpert MTB/RIF assay had a sensitivity and specificity of 83.33% and 100% to detect rifampicin resistance. Bronchoalveolar lavage gene Xpert had a superior diagnostic yield in patients with either smear-negative or sputum-scarce pulmonary tuberculosis. Hence a positive Xpert MTB/RIF assay may be a useful adjunct to diagnosis and detection of MDR-TB in bronchoalveolar lavage specimens

Comparison of sensitivity of quantiFERON-TB gold test and tuberculin skin test in active pulmonary tuberculosis

To compare the sensitivity of tuberculin skin test [TST] and quantiFERON-TB gold test [QFT-G] in active pulmonary tuberculosis. Analytical study. Department of Pulmonology, Fauji Foundation Hospital, Rawalpindi, from July 2011 to January 2012. QuantiFERON-TB gold test [QFT-G] was evaluated and compared it with tuberculin skin test [TST] in 50 cases of active pulmonary tuberculosis, in whom tuberculous infection was suspected on clinical, radiological and microbiological grounds. Sensitivity was determined against postive growth for Mycobacterium tuberculosis. Out of 50 cases, 43 were females and 7 were males. The mean age was 41.84 +/- 19.03 years. Sensitivity of QFT-G was 80% while that of TST was 28%. QFT-G has much higher sensitivity than TST for active pulmonary tuberculosis. It is unaffected by prior BCG administration and prior exposure to atypical mycobacteria. A positive QFT-G result can be an adjunct to diagnosis in patients having clinical and radiological data compatible with pulmonary tuberculosis

Parathyroid carcinoma

Parathyroid carcinoma is a rare endocrine malignancy accounting for less than 1% of all cases of hyperparathyroidism. We present a case of a middle-aged woman who was undiagnosed for 3 years before presenting with renal stones and advanced musculoskeletal disease. Investigations revealed primary hyperparathyroidism. Focused cervical exploration and left inferior parathyroidectomy was carried out based on the pre-operative localization studies. Parathyroid carcinoma was diagnosed on histopathology postoperatively. Subsequent en bloc resection was not performed and the patient is being monitored with serial parathyroid hormone levels which have not shown any increase in 6 months of follow-up. Only two previous cases of parathyroid carcinoma have been reported from Pakistan

Efficacy of zinc as an antibacterial agent against enteric bacterial pathogens

Background: Diarrhoea is a serious threat all over the world with great economic implications especially evident in the developing world. This study was aimed at determining in vitro efficacy of Zinc [Zn] against common enteric bacterial pathogens. Method: A total of 100 bacterial enteric pathogens: Salmonellae [n=16], enteropathogenic Escherichia coli [EPEC] [n=26], Shigellae [n=28] and Vibrio cholerae [n=30] were isolated from diarrhoeal stool specimens at Department of Microbiology, Armed Forces Institute of Pathology Rawalpindi during Aapril 2009 to Jan 2010. These isolates were tested against various concentrations of Zn supplemented in Mueller Hinton [MH] agar using a multipoint inoculator. A minimum inhibitory concentration of active Zn in ZnSO4.7H2O ranging from 0.03 mg/ml to 1 mg/ml was used. Results: Zn completely inhibited the growth of all the tested pathogens and most of them were inhibited at a concentration of 0.06 mg/ml to 0.5 mg/ml of Zn. Conclusions: Zinc has an excellent antibacterial activity against enteric bacterial pathogens common in our setup which may provide basis for treatment of diarrhoea. Clinical study based on these findings is recommended. Keywords: Diarrhoea, zinc, antibacterial, Enteric Pathogens, Cholera, Salmonella, E. coli, Shigella

Evaluation of BACTEC MGIT 960 system for recovery of Mycobacterium tuberculosis complex in Pakistan

We evaluated the performance of MGIT 960 system in terms of recover rate, detection time of mycobacteria and contamination rate from various human clinical specimens and compared it with already in use BACTEC 460 TB system and conventional LJ medium. This is the first reported study on MGIT 960 and its comparison with BACTEC 460 system in Pakistan. A total of 260 different clinical specimens received for the culture of mycobacteria were dealt during the six months study period. All the specimens were digested and decontaminated according to the standard N-acetyl-Lcysteine NaOH method. All the processed specimens were inoculated on both the liquid systems and solid medium and incubated for six weeks and eight weeks consecutively. A total of 44 mycobacterial isolates (Mycobacterium tuberculosis, n=43; Mycobacteria other than tuberculosis, n=1) were recovered from 260 clinical specimens. The recovery rate of M. tuberculosis complex was 97.6% on BACTEC MGIT 960 system and 93.0% on BACTEC 460 system and 83.7% on LJ medium. The mean detection time of mycobacteria on BACTEC MGIT 960 system was 11.2 days in smear positive cases, 14.2 days in smear negative cases and 14.8 days in smear positive cases on BACTEC 460 system. Contamination rates were 9.6% and 5.6% and 3.4% for BACTEC MGIT 960, BACTEC 460 system and LJ medium respectively. The non-radiometric, fully automated BACTEC MGIT 960 system has better diagnostic ability as compared with radiometric, semi-automated BACTEC 460 system and LJ medium, so it can be used as a reliable alternative in over burden laboratories.

In Vitro efficacy of ethionamide and clarithromycin in mycobacterium tuberculosis isolates

To determine the sensitivity of clinical isolates of Mycobacterium tuberculosis isolates against ethionamide, and clarithromycin. Cross-sectional study. Department of Microbiology, Armed Forces Institute of Pathology [AFIP] Rawalpindi from June 2003 to June 2004. All routine clinical samples received for acid fast bacilli [AFB] culture and yielding positive growth on Lowenstien Jensen medium and Bactec 460 were included in the study. The isolates were from sputum [n=70], bronchioalveolar lavage [n=10], fine needle aspiration [n=6], lymph nodes [n=7], pleural fluid [n=4], endometrium [n=3]. After the identification of M. tuberculosis [MTB] sensitivity was performed against first-line antituberculosis drugs. Then susceptibility of M. tuberculosis isolates against ethionamide and clarithromycin was performed on LJ medium. Mycobacterium H37Rv was used as control strain. Results were interpreted using resistance ratio method. Out of 100 M. tuberculosis isolates, sensitivity to ethionamide was 93% and 9% to clarithromycin. Clarithromycin when used alone is ineffective as antituberculosis drug but its efficacy in combination needs to be tested. However ethionamide may be used as an alternative antituberculosis drug

Efficacy of amikacin and ciprofloxacin against clinical isolates of mycobacterium tuberculosis

Tuberculosis was a leading cause of death at the turn of the 20[th] century and continues to be one of the medical scourges of mankind. Before the availability of antimicrobial drugs the cornerstone of treatment was rest in the open air in sanatoria. The major breakthrough in treatment of tuberculosis came with the discovery of Streptomycin. Later, INH, Ethambutol, Pyrazinamide, Rifampicin were added to the arsenal. Objective of this study was to determine the sensitivity of clinical isolates of Mycobacterium tuberculosis against two second-line anti-tuberculosis drugs, Amikacin and Ciprofloxacin. This cross-sectional study was conducted at Department of Microbiology, Armed Forces Institute of Pathology [AFIP] Rawalpindi. All routine clinical samples received for acid fast bacilli [AFB] in the Department of Microbiology, AFIP, Rawalpindi were processed by modified Petroff's technique and inoculated on Lowenstein Jensen [LJ] medium and Bactec 460 Mycobacterium tuberculosis culture system. After identification of M. tuberculosis sensitivity was performed against first-line anti-tuberculosis drugs. Then susceptibility of M. tuberculosis isolates against Amikacin and Ciprofloxacin was performed on LJ medium. H37Rv was used as control strain. Results were interpreted using resistance ratio method. Out of 100 M. tuberculosis isolates, 98% were sensitive to Amikacin and 97% to Ciprofloxacin. Amikacin and Ciprofloxacin are very effective 2[nd] line anti-tuberculosis drugs against tuberculosis isolates in our set-up

Evaluation of readycult coliforms / E. coli test on water samples

To assess the diagnostic accuracy of Readycult Conforms/ E. coli test for microbiological testing of potable water using Multiple Tube Method as gold standard. Study was conducted at Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, from January 2008 through June 2008. This study was a continuum of a previous study. Water samples received within 2 hours of collection were divided aseptically into two equal parts; one part was used for Readycult Conforms/ E. coli test and the other for Multiple Tube Method. Results were interpreted according to WHO guidelines. The sensitivity and specificity of the Readycult Coliforms/ E. coli test was 97% and 95.2% respectively compared to the Gold standard. The positive predictive value and negative predictive value were 94.2% and 98% respectively. Readycult Coliforms/ E. coli test is an effective method for bacteriological testing of water. Results are available within 18-24 hours. This technique can be a useful tool in routine water microbiology particularly in remote areas where laboratory facilities are scarce

Frequency and antimicrobial susceptibility pattern of methicillin resistant Staphylococcus aureus

To determine the frequency of methicillin resistant Staphylococcus aureus and its antimicrobial susceptibility pattern in patients reporting to Combined Military Hospital [CMH], Pano Aqil. A non-interventional, cross-sectional study. Pathology Laboratory, Combined Military Hospital [CMH], Pano Aqil, from December 2005 to January 2008. Strains of Staphylococcus aureus were isolated from a variety of clinical specimens. Standard methodology, using modified Kirby-Bauer disk diffusion method, was adopted for antibiotic sensitivity test. The MIC of oxacillin and vancomycin was performed by E-strips, for MRSA isolates and isolates revealing vancomycin resistance on disk diffusion. A total of 195 hospital and 42 community acquired isolates were tested. Forty-seven [19.8%] non-duplicate strains were found to be methicillin resistant Staphylococcus aureus [MRSA]; methicillin resistance did not differ among hospital strains [n=42] as compared to community ones [n=5, p=0.1555]. No isolates from the community and hospital acquired showed resistance to vancomycin. Community and hospital acquired isolates revealed higher resistance against penicillin and doxycycline than against ciprofloxacin, erythromycin, gentamicin and chloramphenicol. However, resistance against these antibiotics did not differ significantly among community and hospital acquired isolates. Increase in prevalence of MRSA is impending in future, appealing preventive measures to be adopted. However, Staphylococcus aureus resistant to vancomycin was not observed

Catheter associated urinary tract infections in the intensive care unit of tertiary care hospitals: bacterial spectrum and their susceptibility pattern

To determine microbial spectrum of catheter associated urinary tract infection and their antimicrobial susceptibility pattern in patients under intensive care. This is a descriptive and cross-sectional study, which was carried out at the Department of Microbiology Armed Forces Institute of Pathology, Rawalpindi. This institute is providing laboratory cover to two tertiary care hospital and five institutes of excellence. A total of 122 isolates, obtained from urine of 100 catheterized patients, at Armed Forces Institute of Pathology, Rawalpindi for a period of six months were included in the study. Identification was carried out by biochemical and serological profile of the organism. The antimicrobial susceptibility tests of isolated organisms were performed by standard disk diffusion method as recommend by Clinical Laboratory Standards Institute. Majority [68%] of the organisms isolated were Gram negative organisms while 32% of the infections were due to Gram positive organisms/fungi. Moxifloxacin [86.40%] and imipenem [83.30%] were the most active antibiotics. Resistance was very high to ampicillin [88.50%] and trimethoprim /sulfamethoxazole [75.00%]. Majority of the catheter associated urinary tract infections are due to Gram negative but Gram positive organisms and fungi are also causing UTIs in about one third cases. Resistance to the conventional antimicrobials used for UTI was high

Cryptosporidium parvum: public health concern among children of northern areas Pakistan

Cryptosporidium parvum is enteric coccidian parasite that has emerged as an important cause of diarrhea worldwide, particularly in children and immunocompromised individuals. Cryptosporidiosis is endemic in developing countries with the long term effects on growth and development of young children. To determine the frequency of Cryptosporidium parvum infection in young children presenting with diarrhea at Paediatric unit, Combined Military Hospital Gilgit. Descriptive Study was conducted at Department of Pathology, Combined Military Hospital Gilgit, from August 2007 through July 2008. Stool specimens from young children [< 6 years] presenting with watery diarrhea were collected. Modified Ziehl-Neelsen [MZN] staining method was used for diagnosis of cryptosporidium oocysts. Positive cases were further screened for the presence of other parasites ova/cysts by examining wet mount and iodine stained slides of specimens. They were cultured on standard bacteriological medias for the isolation of enteric bacterial pathogens. Cryptosporidium oocysts were found in twenty eight [9.4%] out of 300 children suffering from diarrhea. Giardia cysts were also present in stools of 6 of 28 children. Male to female ratio was 2:1. Infection was more common in children between 6-24 months of age and was associated with abdominal pain. Out of 28 cases 20 [71%] had acute watery diarrhoea and 8 [29%] presented with chronic diarrhoea. Direct or indirect contact with domestic animals was present in most of the C. parvum infected children. C. parvum is an important cause of diarrhea in young children and frequency Cryptosporidium is considerably high. Laboratory investigations for Cryptosporidium should be encouraged to consider when young patients present with watery stool

Rapid detection of methicillin resistant staphylococci from the nasal screening swabs by mannitol salt agar with cefoxitin and oxacillin disks

To assess the reliability of Manitol salt agar [MSA] for directly identifying Methicillin Resistant Staphylococcus aureus [MRSA] and Methicillin Resistant Coagulase negative Staphylococci, [MRCoNS] in nasal swabs for screening purposes using cefoxitin and oxacillin disks. Descriptive and Quasi-experimental. The study was done in the two surgical units of Combined Military Hospital, Rawalpindi and all the samples were processed at the Department of Microbiology, Armed forces Institute of Pathology, Rawalpindi during July 2007. A total of eighty four duplicate swabs were taken from the anterior nares of various staff members of the two surgical units and were directly inoculated on Mannitol salt agar with Cefoxitin disc 30 micro g [MSAFOX] and oxacillin disc 1 micro g [MSAOX]. All the samples were simultaneously inoculated on blood and MacConkey agar for conventional testing, using standard conditions, and confirmed as MRSA or MRCoNS by oxacillin disk diffusion technique. The staphylococcal isolates were later confirmed as MRSA/MRCoNS by polymerase chain reaction [PCR] for mec A gene analysis. There were 45 staphylococci which revealed mec A gene [40 MRCoNS and 5 MRSA] by PCR. Both the disks with MSA effectively identified the methicillin resistance. MSA with cefoxitin could identify 40 methicillin resistant staphylococci [35 MRCoNS and 5 MRSA] where as MSA with oxacillin could identify 39 methicillin resistant staphylococci [34 MRCoNS and 4 MRSA]. There was no significant difference between the two disks in sensitivity, specificity, positive and negative predictive values and overall efficacy of the procedures. MSA with cefoxitin 30 micro g and oxacillin 1 micro g appear to be highly accurate, easy to perform and beneficial for quick and reliable detection of methicillin resistant staphylococci from the nasal carriers in a routine microbiology laboratory

Percentage of hepatitis B and C among young adult males from interior Sindh

Present study was planned to know the seropercentage of Hepatitis C Antibodies and Hepatitis B Surface Antigen in a population based sample of healthy male army/naval recruits from rural Sindh. Laboratory based non-interventional, descriptive study. Conducted at Combined Military Hospital Pano Aqil from 1st January 2006 to 31st October 2006.A total of 5237 healthy male recruits from various districts of interior Sind were studied. HBsAg and Anti-HCV were tested by Immunochromatographic assay and positive tests were confirmed by ELISA method. The percentage of anti-HCV was [4.37%] and was [7.39%] for HBsAg. The percentage of HBsAg in districts Nowsheroferoze [10.11%], Ghotki [9.21%] and Khairpur [7.48%] and Anti-HCV [p<0.0001] in districts Nawabshah [9.32%], Khairpur [6.71%] and Ghotki [6.64%] respectively was higher than the other districts. Both the viruses are evenly distributed among the remaining different Districts` population. There is considerable threat of HBV and HCV in interior Sindh. Screening of selected groups and vaccination against Hepatitis B may be considered in these areas. Health education to general public including barbers would be the key for control/prevention of these dreadful diseases

Renal cell carcinomas: Correlation of size with tumor grade and extracapsular extension

To find the association of tumor size with grade of tumor and its extra capsular extension. A review of record of all renal biopsies performed at pathology department King Edward Medical University over a period of two years was done. It was found that large sized tumors tend to have a higher grade and this correlation was found to be statistically significant [P=0.02]. A significant correlation was also seen between the size of tumor and extra capsular extension [P=0.001]. It was concluded patients presenting with larger renal tumors, who subsequently underwent nephrectomy and histopathological analysis were diagnosed with a higher grade. This relation implies that these patients with larger tumors will in turn have poorer prognosis

Validity of nalidixic acid screening in fluoroquinolone-resistant typhoid salmonellae

To validate the screening of low-level fluoroquinolone resistance in typhoid salmonellae by using nalidixic acid [30mg] disk providing an acceptable zone of inhibition. Quasi-experimental study. The Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, Pakistan from July 2002 to June 2003. Antimicrobial susceptibility of 225 clinical isolates of S. typhi [n=126] and S. paratyphi A [n=99] against nalidixic acid and ciprofloxacin was determined by the modified Kirby-Bauer disk diffusion and agar dilution techniques of NCCLS. The relationship between the zone sizes and the MICs of the two quinolones was plotted in the form of scattergrams and nalidixic acid MICs and zone of inhibition sizes were correlated with those of ciprofloxacin by regression analysis. One hundred and ninety-five isolates were nalidixic acid-susceptible [MIC <16 Mug/mL] and 30 were nalidixic acid-resistant [MIC >32 Mug/mL]. All the nalidixic acid-susceptible isolates had ciprofloxacin MIC of <0.064 Mug/mL. Among the nalidixic acid-resistant isolates 20 had ciprofloxacin MIC > 0.125 Mug/mL and 10 had ciprofloxacin MIC < 0.03- 0.064 Mug/mL. The diameter of inhibition zone around a 30 mg nalidixic acid disk of nalidixic acid-resistant isolates was <13 mm [range 6-16 mm, mean 10.3 mm + SD 3.5 mm], while among nalidixic acid-susceptible isolates it ranged from 14 to 30 mm [mean 23.8 mm + SD 2.2 mm]. The diameter of inhibition zone around a 5mg ciprofloxacin disk of nalidixic acidresistant isolates ranged from 26 to 35 mm [mean 29.8 mm + SD 3.1 mm], while in nalidixic acid-susceptible isolates it ranged from 32 to 42 mm [mean 36.6 mm + SD 1.9 mm]. With ciprofloxacin MIC Z WITH CARON0.125 mg/mL taken as a breakpoint, a zone of <33mm around a 5mg ciprofloxacin disk to detect low susceptibility strains had a sensitivity of 100% and a specificity of 82%. Screening for nalidixic acid resistance [inhibition zone diameter of <13 mm] in isolates with ciprofloxacin MIC Z WITH CARON 0.125 mg/mL using a 30 mg nalidixic acid disk yielded a sensitivity of 100% and a specificity of 95%. Screening for nalidixic acid resistance with a 30mg nalidixic acid disk is a reliable and cost-effective method for detection of low-level fluoroquinolone resistance in typhoid salmonellae